Signal generation apparatus

ABSTRACT

A signal generation apparatus for use with a ToF camera system includes a first pulse generator configured to generate a pulse to be supplied to a light source that irradiates light to a distance measurement target, a second pulse generator configured to generate a pulse to be supplied to pixels that receive light reflected by the distance measurement target, and a switching section configured to switch a setting of a modulation frequency of the first pulse generator and the second pulse generator within a predetermined period.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit under 35 U.S.C. § 371 as a U.S.National Stage Entry of International Application No. PCT/JP2018/039649,filed in the Japanese Patent Office as a Receiving Office on Oct. 25,2018, which claims priority to Japanese Patent Application NumberJP2017-245948, filed in the Japanese Patent Office on Dec. 22, 2017,each of which is hereby incorporated by reference in its entirety.

TECHNICAL FIELD

The present disclosure relates to a signal generation apparatus.

BACKGROUND ART

A time-of-flight (ToF) camera system is a system in which a period oftime after light is emitted from a light source until the light returnsafter it is reflected by an object is analyzed to derive informationrelating to the distance to the object. An example of application of theToF camera system is a camera that can take in a three-dimensional (3D)image of a scene, namely, two-dimensional information and depth, namely,distance, information. Such a camera system as just described isutilized in many application examples in which it is necessary to decidethe depth from a fixed point, namely, distance information. Generally,depth information, namely, distance information, is measured from a ToFcamera system.

As the distance measurement system of the ToF camera system, a directsystem of measuring the distance by directly measuring the time and anindirect system of measuring the distance indirectly from the exposureamount. The indirect system is higher in accuracy, and it is expectedthat a ToF camera system that adopts the indirect system spreads widely.As a literature that discloses a ToF camera system that adopts theindirect system, for example, PTL 1 and so forth are available.

CITATION LIST Patent Literature

[PTL 1]

Japanese Patent Laid-Open No. 2016-224062

SUMMARY Technical Problem

In a distance image sensor of an indirect ToF type, the modulationfrequency and the distance measurement error have an inverseproportional relationship to each other. Although, in order to increasethe accuracy to perform distance measurement, it is necessary to raisethe modulation frequency, if the modulation frequency is increase, thenthe distance measurement range becomes narrower.

Therefore, the present disclosure proposes a signal generation apparatusfor use with a ToF camera system that especially adopts the indirectsystem, which is novel and improved in that it can be ready for variousmodulation frequencies with a simple configuration.

Solution to Problem

According to the present disclosure, there is provided a signalgeneration apparatus including a first pulse generator configured togenerate a pulse to be supplied to a light source that irradiates lightto a distance measurement target, a second pulse generator configured togenerate a pulse to be supplied to pixels that receive light reflectedby the distance measurement target, and a switching section configuredto switch a setting of a modulation frequency of the first pulsegenerator and the second pulse generator within a predetermined period.

Advantageous Effect of Invention

As described above, with the present disclosure, a novel and improvedsignal generation apparatus for use with a ToF camera system thatespecially adopts the indirect system, which can be ready for variousmodulation frequencies with a simple configuration.

It is to be noted that the advantageous effect described above is notnecessarily restrictive, and some advantageous effects indicated in thepresent specification or other advantageous effects that can berecognized from the present specification may be applicable togetherwith the advantageous effect described above or in place of theadvantageous effect described above.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a block diagram depicting a configuration example of a firstembodiment of a sensor chip to which the present technology is applied.

FIG. 2 is a view depicting a configuration example of a globalcontrolling circuit.

FIG. 3 is a view depicting a configuration of a rolling controllingcircuit.

FIG. 4 is a block diagram depicting a first modification of a sensorchip of FIG. 1.

FIG. 5 is a block diagram depicting a second modification of the sensorchip of FIG. 1.

FIG. 6 is a block diagram depicting a configuration example of a secondembodiment of the sensor chip.

FIG. 7 is a perspective view depicting a configuration example of athird embodiment of the sensor chip.

FIG. 8 is a block diagram depicting the configuration example of thethird embodiment of the sensor chip.

FIG. 9 is a block diagram depicting a first modification of the sensorchip of FIG. 8.

FIG. 10 is a block diagram depicting a second modification of the sensorchip of FIG. 8.

FIG. 11 is a block diagram depicting a configuration example of a fourthembodiment of the sensor chip.

FIG. 12 is a block diagram depicting a configuration example of a fifthembodiment of the sensor chip.

FIG. 13 is a perspective view depicting a configuration example of asixth embodiment of the sensor chip.

FIG. 14 is a block diagram depicting the configuration example of thesixth embodiment of the sensor chip.

FIG. 15 is a block diagram depicting a first modification of the sensorchip of FIG. 14.

FIG. 16 is a block diagram depicting a second modification of the sensorchip of FIG. 14.

FIG. 17 is a block diagram depicting a third modification of the sensorchip of FIG. 14.

FIG. 18 is a block diagram depicting a fourth modification of the sensorchip of FIG. 14.

FIG. 19 is a block diagram depicting a fifth modification of the sensorchip of FIG. 14.

FIG. 20 is a block diagram depicting a sixth modification of the sensorchip of FIG. 14.

FIG. 21 is a block diagram depicting a seventh modification of thesensor chip of FIG. 14.

FIG. 22 is a block diagram depicting an eighth modification of thesensor chip of FIG. 14.

FIG. 23 is a perspective view depicting a configuration example of aseventh embodiment of the sensor chip.

FIG. 24 is a perspective view depicting a first modification of thesensor chip of FIG. 23.

FIG. 25 is a perspective view depicting a second modification of thesensor chip of FIG. 23.

FIG. 26 is a block diagram depicting a configuration example of an eightembodiment of the sensor chip and a modification of the same.

FIG. 27 is a block diagram depicting a configuration example of animaging apparatus.

FIG. 28 is an explanatory view depicting a functional configurationexample of a pulse generator 300 according to an embodiment of thepresent disclosure.

FIG. 29 is an explanatory view of an example of waveforms of signals.

FIG. 30 is an explanatory view depicting a schematic configurationexample of a distance image sensor.

FIG. 31 is an explanatory view depicting an example of phase setting.

FIG. 32 is an explanatory view depicting a schematic configurationexample of a distance image sensor.

FIG. 33 is an explanatory view depicting another example of phasesetting.

FIG. 34 is an explanatory view depicting a schematic configurationexample of the distance image sensor.

FIG. 35 is an explanatory view depicting an example of phase setting.

FIG. 36 is an explanatory view depicting an example of a signaloutputted from a pulse generator and a phase setting inputted to thepulse generator.

FIG. 37 is an explanatory view depicting an example of a waveform of alight source output signal generated by the pulse generator 300 andhaving a duty of 50%.

FIG. 38 is an explanatory view depicting a manner in which a distancemeasurement error is caused by a cyclic error.

FIG. 39 is an explanatory view depicting an example of a waveform oflight source output signals where the duty is 30% and 25% lower than50%.

FIG. 40 is an explanatory view depicting a configuration example foroutputting a light source outputting signal in a distance image sensor.

FIG. 41 is an explanatory view depicting an overview of generation of alight source outputting signal where the duty is set lower than 50%.

FIG. 42 is an explanatory view depicting an example of light sourcephase setting.

FIG. 43 is an explanatory view depicting an example of waveforms ofsignals.

FIG. 44 is an explanatory view depicting a driving example of thedistance image sensor.

FIG. 45 is a flow chart depicting an operation example of the distanceimage sensor.

FIG. 46 is an explanatory view depicting an operation example of adistance image sensor of an indirect ToF type.

FIG. 47 is an explanatory view depicting an operation example of thedistance image sensor of the indirect ToF type.

FIG. 48 is an explanatory view depicting an operation example of thedistance image sensor of the indirect ToF type.

FIG. 49 is an explanatory view depicting a particular example of drivingof the distance image sensor of the indirect ToF type.

FIG. 50 is an explanatory view depicting an example of a configurationused in the distance image sensor of the indirect ToF type.

FIG. 51 is an explanatory view depicting a manner in which light isradiated from a plurality of light sources toward a same distancemeasurement target and a certain image sensor receives the light fromthem.

FIG. 52 is an explanatory view depicting a manner in which an overlap oflight emission time (modulation time) occurs between a light source Aand another light source B.

FIG. 53 is an explanatory view depicting a manner in which a lightemission timing is displaced at random between the light source A andthe light source B.

FIG. 54 is an explanatory view depicting an example of a pixelmodulation signal.

FIG. 55 is an explanatory view illustrating generation of a pseudorandom pulse used in the present embodiment.

FIG. 56 is an explanatory view depicting an example of signals.

FIG. 57 is an explanatory view depicting a configuration example used inthe distance image sensor of the indirect ToF method.

FIG. 58 is an explanatory view depicting an example in which the phaseof a modulation signal varies on the basis of a state transition of thepseudo random pulse.

FIG. 59 is an explanatory view depicting an example in which the phaseof a modulation signal varies on the basis of a state transition of thepseudo random pulse.

FIG. 60 is an explanatory view depicting an example in which the phaseof a modulation signal varies on the basis of a state transition of thepseudo random pulse.

FIG. 61 is an explanatory view depicting an example in which the phaseof a modulation signal varies on the basis of a state transition of thepseudo random pulse.

FIG. 62 is an explanatory view depicting an example of a configurationthat selects and outputs two signals having different duties from eachother from two pulse generators.

FIG. 63 is an explanatory view depicting an example of a waveform of asignal having a duty smaller than 50% and a waveform of a signalgenerated on the basis of a pseudo random pulse, which are generatedfrom a pulse generator.

FIG. 64 is a view depicting an example of a schematic configuration ofan endoscopic surgery system.

FIG. 65 is a block diagram depicting an example of a functionalconfiguration of a camera head and a CCU.

FIG. 66 is a block diagram depicting an example of schematicconfiguration of a vehicle control system.

FIG. 67 is a diagram of assistance in explaining an example ofinstallation positions of an outside-vehicle information detectingsection and an imaging section.

DESCRIPTION OF EMBODIMENTS

In the following, a preferred embodiment of the present disclosure isdescribed in detail with reference to the accompanying drawings. It isto be noted that, in the present specification and drawings, componentshaving substantially same functional configurations are denoted by likereference characters and overlapping description of them is omitted.

It is to be noted that the description is given in the following order.

1. Embodiment of Present Disclosure

-   -   1.1. Overview    -   1.2. Configuration Example of Sensor Chip    -   1.3. Particular Configuration Example of Distance Image Sensor

2. Summary

1. EMBODIMENT OF PRESENT DISCLOSURE

[1.1. Overview]

First, an overview of the embodiment of the present disclosure isdescribed.

A ToF camera system is a system in which a period of time after light isemitted from a light source until the light returns after it isreflected by an object is analyzed to derive information relating to thedistance to the object. An example of application of the ToF camerasystem is a camera that can take in a three-dimensional (3D) image of ascene, namely, two-dimensional information and depth, namely, distance,information. Such a camera system as just described is utilized in manyapplication examples in which it is necessary to decide the depth from afixed point, namely, distance information. Generally, depth information,namely, distance information, is measured from a ToF camera system.

As the distance measurement system of the ToF camera system, a directsystem of measuring the distance by directly measuring the time and anindirect system of measuring the distance indirectly from the exposureamount. The indirect system is higher in accuracy, and it is expectedthat a ToF camera system that adopts the indirect system spreads widely.

The disclosing person of the present case has improved a ToF camerasystem that adopts the conventional direct method and has conceived aToF camera system that adopts the indirect system and a configurationthat is used in the ToF camera system, which can increase the accuracyin distance measurement with a simple configuration as described below.

[1.2. Configuration Example of Sensor Chip]

<First Configuration Example of Sensor Chip>

FIG. 1 is a block diagram depicting a configuration example of a firstembodiment of a sensor chip to which the present technology is applied.

As depicted in FIG. 1, the sensor chip 11 is configured including apixel array section 12, a global controlling circuit 13, a rollingcontrolling circuit 14, a column ADC (Analog-to-Digital Converter) 15and an inputting and outputting section 16, which are disposed on asemiconductor substrate.

The pixel array section 12 is a rectangular region in which varioussensor elements according to functions of the sensor chip 11, forexample, photoelectric conversion elements that perform photoelectricconversion of light, are disposed in an array. In the example depictedin FIG. 1, the pixel array section 12 is a horizontally elongatedrectangular region having a long side extending in the horizontaldirection and a short side extending in the vertical direction.

The global controlling circuit 13 is a control circuit that outputs aglobal controlling signal for controlling the plurality of sensorelements disposed in the pixel array section 12 such that they aredriven all at once (simultaneously) at a substantially same timing. Inthe configuration example of FIG. 1, the global controlling circuit 13is disposed on the upper side of the pixel array section 12 such thatthe longitudinal direction thereof extends along a long side of thepixel array section 12. Accordingly, in the sensor chip 11, a controlline 21 for supplying the global controlling signal outputted from theglobal controlling circuit 13 to the sensor elements of the pixel arraysection 12 is disposed in the upward and downward direction of the pixelarray section 12 for each column of the sensor elements disposed in amatrix in the pixel array section 12.

The rolling controlling circuit 14 is a control circuit that outputsrolling controlling signals for controlling the plurality of sensorelements disposed in the pixel array section 12 such that the sensorelements are successively (sequentially) driven in order for each row.In the configuration example depicted in FIG. 1, the rolling controllingcircuit 14 is disposed on the right side of the pixel array section 12such that the longitudinal direction thereof extends along a short sideof the pixel array section 12.

The column ADC 15 converts analog sensor signals outputted from thesensor elements of the pixel array section 12 to digital values with AD(Analog-to-Digital)) in parallel for the individual columns. At thistime, the column ADC 15 can remove reset noise included in the sensorsignals, for example, by performing a CDS (Correlated Double Sampling:correlated double sampling) process for the sensor signals.

The inputting and outputting section 16 has provided thereon terminalsfor performing inputting and outputting between the sensor chip 11 andan external circuit, and for example, power necessary for driving theglobal controlling circuit 13 is inputted to the sensor chip 11, forexample, through the inputting and outputting section 16. In theconfiguration example depicted in FIG. 1, the inputting and outputtingsection 16 is disposed along the global controlling circuit 13 such thatit is positioned adjacent the global controlling circuit 13. Forexample, since the global controlling circuit 13 has high powerconsumption, in order to reduce the influence of an IR drop (voltagedrop), preferably the inputting and outputting section 16 is disposed inthe proximity of the global controlling circuit 13.

The sensor chip 11 is configured in this manner, and a layout in whichthe global controlling circuit 13 is disposed so as to extend along along side of the pixel array section 12 is adopted. Consequently, thedistance from the global controlling circuit 13 to a sensor elementdisposed at the remote end of the control line 21 (the lower end in theexample of FIG. 1) can be made shorter than that in an alternativelayout in which the global controlling circuit 13 is disposed so as toextend along a short side of the pixel array section 12.

Accordingly, since the sensor chip 11 can improve the delay amount andthe slew rate that occur with a global controlling signal outputted fromthe global controlling circuit 13, it can perform control for the sensorelements at a high speed. Especially, in the case where the sensor chip11 is an image sensor that performs global shutter driving, high speedcontrol of a transfer signal or a reset signal to be supplied to thepixels, an overflow gate signal and so forth becomes possible. On theother hand, in the case where the sensor chip 11 is a ToF sensor, highspeed control of a MIX signal becomes possible.

For example, in a ToF sensor, a fluorescence detection sensor or thelike, if the slew rate of a global controlling signal or the delayamount of a global controlling signal, which occurs in accordance withthe distance from a driving element, or the like differs for each sensorelement, then this gives rise to a detection error. In contrast, sincethe sensor chip 11 can improve the delay amount and the slew rage thatoccur in the global controlling signal as described above, such adetection error as described above can be suppressed.

Further, in the case where the sensor chip 11 is a ToF sensor, afluorescence detection sensor or the like, not only such a number oftimes of on/off control as may exceed 100 times is required for anexposure period but also the current consumption increases because thetoggle frequency is high. In contrast, in the sensor chip 11, theinputting and outputting section 16 can be disposed in the proximity ofthe global controlling circuit 13 as described above such that anindependent wiring line can be provided for the power supply.

Further, while, in the sensor chip 11, the global controlling circuit 13frequently operates during an exposure period, the rolling controllingcircuit 14 remains stopping. On the other hand, in the sensor chip 11,while the rolling controlling circuit 14 operates within a reading outperiod, the global controlling circuit 13 frequently is stopping.Therefore, in the sensor chip 11, it is demanded to control the globalcontrolling circuit 13 and the rolling controlling circuit 14independently of each other. Further, in the sensor chip 11, in order tosecure in-plane synchronization, it is general to adopt such a clocktree structure depicted in FIG. 2C as hereinafter described, preferablythe global controlling circuit 13 is disposed independently of therolling controlling circuit 14.

Accordingly, in the case where higher speed control is demanded as inthe sensor chip 11, better control can be anticipated by adopting thelayout in which the global controlling circuit 13 and the rollingcontrolling circuit 14 are individually and independently of each other.It is to be noted, if the global controlling circuit 13 and the rollingcontrolling circuit 14 are disposed individually and independently ofeach other, then any one of a layout in which they extend along a samedirection and another layout in which they extend orthogonally to eachother may be adopted.

It is to be noted that, although, in the description of the presentembodiment, it is described that the upper side in each figure is theupper side of the pixel array section 12 and the lower side in eachfigure is the lower side of the pixel array section 12 in accordancewith the configuration example depicted, if, for example, the globalcontrolling circuit 13 is disposed so as to extend along a long side ofthe pixel array section 12, then similar working effects can be achievedon whichever one of the upper side and the lower side the globalcontrolling circuit 13 is disposed. Further, this similarly applies alsoto the pixel array section 12 and the column ADC 15.

A configuration of the global controlling circuit 13 is described withreference to FIG. 2.

FIG. 2A depicts a first configuration example of the global controllingcircuit 13; FIG. 2B depicts a second configuration example of the globalcontrolling circuit 13; and FIG. 2C depicts a third configurationexample of the global controlling circuit 13. It is to be noted that,although the global controlling circuit 13 is configured such that itsimultaneously outputs global controlling signals in accordance with thenumber of columns of sensor elements disposed in the pixel array section12, in FIG. 2, as part of the configuration, a configuration thatoutputs eight global controlling signals at the same time isschematically depicted.

The global controlling circuit 13 depicted in FIG. 2A is configuredincluding one internal buffer 31 and eight driving elements 32 a to 32h.

As depicted in FIG. 2A, the global controlling circuit 13 has such aconnection configuration that the internal buffer 31 is connected to oneend of an internal wiring line provided along the longitudinal directionand the driving elements 32 a to 32 h are connected to the internalwiring line toward one direction according to the positions of thecontrol lines 21. Accordingly, a global controlling signal inputted tothe global controlling circuit 13 is supplied from one end side of theinternal wiring line (in the example of FIG. 2, the left side) to thedriving elements 32 a to 32 h through the internal buffer 31 and issimultaneously outputted to the control lines 21 individually connectedto the driving elements 32 a to 32 h.

The global controlling circuit 13A depicted in FIG. 2B is configuredincluding two internal buffers 31 a and 31 b and eight driving elements32 a to 32 h.

As depicted in FIG. 2B, the global controlling circuit 13A has such aconnection configuration that the internal buffers 31 a and 31 b areconnected to the opposite ends of an internal wiring line provided alongthe longitudinal direction of the global controlling circuit 13A and thedriving elements 32 a to 32 h are connected to the internal wiring linetoward one direction according to the positions of the control lines 21of FIG. 1.

Accordingly, a global controlling signal inputted to the globalcontrolling circuit 13A is supplied from the opposite ends of theinternal wiring line through the internal buffers 31 a and 31 b to thedriving elements 32 a to 32 h and is simultaneously outputted to thecontrol lines 21 individually connected to the driving elements 32 a to32 h.

The global controlling circuit 13B depicted in FIG. 2C is configuredincluding seven internal buffers 31 a to 31 g and eight driving elements32 a to 32 h.

As depicted in FIG. 2C, the global controlling circuit 13B has such aconnection configuration that a clock tree structure is configured fromthe internal buffers 31 a to 31 g and, in the final stage, it isconnected to the driving elements 32 a to 32 h disposed along onedirection according to the positions of the control lines 21. Forexample, the clock tree structure is such a structure that a structurethat, in the first stage, an output of one internal buffer 31 isinputted to two internal buffers 31 and, in the second state, inputs ofthe two internal buffers 31 are inputted to four internal buffers 31 isrepeated in a plurality of stages. Accordingly, a global controllingsignal inputted to the global controlling circuit 13B is supplied to thedriving elements 32 a to 32 h through the clock tree structureconfigured from the internal buffers 31 a to 31 g and is simultaneouslyoutputted to the control lines 21 connected to the driving elements 32 ato 32 h.

The global controlling circuit 13B having such a configuration asdescribed above can avoid occurrence of a delay between the drivingelements 32 a to 32 h and can ensure in-plane uniformity, for example,in comparison with the global controlling circuits 13 and 13A. In otherwords, it is preferable to adopt the global controlling circuit 13B inan application in which synchronization is requested strongly over adirection in which the driving elements 32 are lined up.

A configuration of the rolling controlling circuit 14 is described withreference to FIG. 3.

FIG. 3A depicts a first configuration example of the rolling controllingcircuit 14, and FIG. 3B depicts a second configuration example of therolling controlling circuit 14. It is to be noted that, although therolling controlling circuit 14 is configured such that it sequentiallyoutputs rolling controlling signals according to the row number of thesensor elements disposed in the pixel array section 12, in FIG. 3, aspart of the configuration, a configuration that outputs eight rollingcontrolling signals sequentially is schematically depicted.

The rolling controlling circuit 14 depicted in FIG. 3A adopts a shiftregister system and is configured including two internal buffers 41 and42, eight registers 43 a to 43 h and eight driving elements 44 a to 44h. It is to be noted that, although the configuration example in whichtwo internal buffers 41 and 42 are disposed is depicted forsimplification, a configuration may otherwise be adopted in which aplurality of internal buffers are disposed according to wiring linelengths of the internal buffers.

As depicted in FIG. 3A, the rolling controlling circuit 14 has such aconnection configuration that the internal buffer 41 is connected to oneend of an internal wiring line provided along the longitudinal directionand the registers 43 a to 43 h are connected to the internal wiring lineaccording to the positions of the rows of the sensor elements disposedin the pixel array section 12. Further, the rolling controlling circuit14 has such a connection configuration that the internal buffer 42 isconnected to the register 43 a and the registers 43 a to 43 h areconnected sequentially and besides the driving elements 44 a to 44 h areconnected to the registers 43 a to 43 h, respectively.

Accordingly, in the rolling controlling circuit 14, a start pulsesupplied to the register 43 a through the internal buffer 42 issequentially shifted to the registers 43 a to 43 h in accordance with aclock supplied through the internal buffer 41 and is sequentiallyoutputted as rolling controlling signals from the driving elements 44 ato 44 h connected to the registers 43 a to 43 h, respectively.

The rolling controlling circuit 14A depicted in FIG. 3B adopts a decodersystem and is configured including two internal buffers 41 and 42, adecoder 45, eight AND gates 46 a to 46 h and eight driving elements 44 ato 44 h. It is to be noted that, for the decoder 45, any one of adecoder of a type that includes a latch and a decoder of another typethat does not include a latch may be used. For example, in the casewhere the decoder 45 is of the type that latches a signal, a system bywhich addresses are sent at once, another system by which addresses aresent divisionally or the like can be adopted.

As depicted in FIG. 3B, in the rolling controlling circuit 14A, theinternal buffer 41 is connected to the decoder 45, and the internalbuffer 42 is connected to an input terminal of the AND gates 46 a to 46h and the decoder 45 is connected to an input terminal of the AND gates46 a to 46 h for each row. Further, the rolling controlling circuit 14Ahas a connection configuration in which output terminals of the ANDgates 46 a to 46 h are connected to the driving elements 44 a to 44 h,respectively.

Accordingly, in the rolling controlling circuit 14A, a pulse supplied tothe AND gates 46 a to 46 h through the internal buffer 42 issequentially outputted as rolling controlling signals from the drivingelements 44 a to 44 h of rows designated by addresses supplied to thedecoder 45 through the internal buffer 41.

As described with reference to FIGS. 2 and 3, the global controllingcircuit 13 and the rolling controlling circuit 14 have circuitconfigurations different from each other.

FIG. 4 is a block diagram depicting a first modification of the sensorchip 11 depicted in FIG. 1. It is to be noted that, from among blocksconfiguring the sensor chip 11-a depicted in FIG. 4, components commonto those of the sensor chip 11 of FIG. 1 are denoted by like referencecharacters, and detailed description of them is omitted.

In particular, as depicted in FIG. 4, the sensor chip 11-a has aconfiguration common to the sensor chip 11 of FIG. 1 in terms of thedisposition of the pixel array section 12, rolling controlling circuit14, column ADC 15 and inputting and outputting section 16.

Meanwhile, the sensor chip 11-a has a configuration different from thatof the sensor chip 11 of FIG. 11 in that two global controlling circuits13-1 and 13-2 are disposed so as to extend along the upper side and thelower side of the pixel array section 12, respectively, and the drivingelements 32-1 and 32-2 are connected to the opposite ends of the controlline 21. In particular, the sensor chip 11-a is configured such that thedriving element 32-1 included in the global controlling circuit 13-1supplies a global controlling signal from the upper end of the controlline 21 and the driving element 32-2 included in the global controllingcircuit 13-2 supplies a global controlling signal from the lower end ofthe control line 21.

The sensor chip 11-a configured in this manner can suppress a skewbetween the two driving element 32-1 and driving element 32-2 and caneliminate a dispersion in delay time that occurs in global controllingsignals propagated along the control line 21. Consequently, in thesensor chip 11-a, control for the sensor elements can be performed at ahigher speed. It is to be noted that, in the sensor chip 11-a, it isnecessary to perform the control such that the delay difference inoutputting of global controlling signals is avoided from becoming greatsuch that through current may not be generated.

FIG. 5 is a block diagram depicting a second modification of the sensorchip 11 depicted in FIG. 1. It is to be noted that, from among blocksconfiguring the sensor chip 11-b depicted in FIG. 5, components commonto those of the sensor chip 11 of FIG. 1 are denoted by like referencecharacters, and detailed description of them is omitted.

In particular, as depicted in FIG. 5, the sensor chip 11-b is configuredcommonly to the sensor chip 11 of FIG. 1 in terms of the disposition ofthe sensor chip 11-b, pixel array section 12, rolling controllingcircuit 14, column ADC 15 and inputting and outputting section 16.

On the other hand, the sensor chip 11-b has a different configurationfrom that of the sensor chip 11 of FIG. 1 in that the two globalcontrolling circuits 13-1 and 13-2 are disposed so as to extend alongthe upper side and the lower side of the pixel array section 12,respectively, and the two control lines 21-1 and 21-2 are disposed suchthat they are separate at the center of a column of the sensor elementsdisposed in a matrix in the pixel array section 12. Further, in thesensor chip 11-b, the driving element 32-1 is connected to an upper endof the control line 21-1, and the driving element 32-2 is connected to alower end of the control line 21-2.

Accordingly, the sensor chip 11-b is configured such that, to the sensorelements disposed on the upper side with respect to the center of thepixel array section 12, the driving element 32-1 included in the globalcontrolling circuit 13-1 supplies a global controlling signal from theupper end of the control line 21-1. Further, the sensor chip 11-b isconfigured such that, to the sensor elements disposed on the lower sidewith respect to the center of the pixel array section 12, the drivingelement 32-2 included in the global controlling circuit 13-2 supplies aglobal controlling signal from the lower end of the control line 21-2.

According to the sensor chip 11-b configured in this manner, thedistance from the driving element 32-1 to a sensor element disposed atthe remote end (in the example of FIG. 5, the lower end) of the controlline 21-1 and the distance from the driving element 32-2 to a sensorelement disposed at the remote end (in the example of FIG. 5, the upperend) of the control line 21-2 can made shorter, for example, than thatin the sensor chip 11 of FIG. 1. Consequently, the sensor chip 11-b canperform control for the sensor elements at a further higher speedbecause the delay amount and the slew rate occurring with globalcontrolling signals outputted from the global controlling circuits 13-1and 13-2 can be further reduced.

<Second Configuration Example of Sensor Chip>

A second embodiment of a sensor chip to which the present technology isapplied is described with reference to FIG. 6. It is to be noted that,from among blocks configuring the sensor chip 11A depicted in FIG. 6,components common to those of the sensor chip 11 of FIG. 1 are denotedby like reference characters, and detailed description of them isomitted.

As depicted in FIG. 6, the sensor chip 11A is configured such that apixel array section 12A, a global controlling circuit 13A, a rollingcontrolling circuit 14A, a column ADC 15A and an inputting andoutputting section 16A are disposed on a semiconductor substrate.

The sensor chip 11A is different in configuration from the sensor chip11 of FIG. 1 in that the pixel array section 12A is a verticallyelongated rectangular area in which the longer sides are provided toextend in the vertical direction and the shorter sides are provided toextend in the horizontal direction. Accordingly, in the sensor chip 11A,the global controlling circuit 13A and the inputting and outputtingsection 16A are disposed on the left side of the pixel array section 12Aso as to extend along a long side of the pixel array section 12A. Withthis, a control line 21A is disposed, for each row of the sensorelements disposed in a matrix in the pixel array section 12A, toward theleftward and rightward direction of the pixel array section 12A.

Further, in the sensor chip 11A, the rolling controlling circuit 14A isdisposed on the right side of the pixel array section 12A (on the sideopposing to the global controlling circuit 13A) so as to extend along along side of the pixel array section 12A. It is to be noted that,although the global controlling circuit 13A and the pixel array section12A may be disposed on the same side with respect to the pixel arraysection 12A, in this case, since it is supposed that the wiring linelength of any one of them becomes longer, it is preferable to adopt sucharrangement as depicted in FIG. 6.

Further, in the sensor chip 11A, the column ADC 15A is disposed on thelower side of the pixel array section 12A so as to extend along a shortside of the pixel array section 12A. The reason why the column ADC 15Ais disposed in a direction orthogonal to the rolling controlling circuit14A in this manner is that it is necessary to turn on the sensorelements connected to one AD converter one by one, and such a layoutthat individual wiring lines overlap with each other is avoided.

According to the sensor chip 11A configured in this manner, the wiringline length of the control line 21A can be reduced by the layout inwhich the global controlling circuit 13A is disposed so as to extendalong a long side of the pixel array section 12A similarly to the sensorchip 11 of FIG. 1. Accordingly, the sensor chip 11A can perform controlfor the sensor elements at a higher speed similarly to the sensor chip11 of FIG. 1.

<Third Configuration Example of Sensor Chip>

A third embodiment of a sensor chip to which the present technology isapplied is described with reference to FIGS. 7 to 10. It is to be notedthat, from among blocks configuring the sensor chip 11B depicted inFIGS. 7 to 10, components common to those of the sensor chip 11 of FIG.1 are denoted by like reference characters, and detailed description ofthem is omitted.

FIG. 7 depicts a perspective view of the sensor chip 11B, and FIG. 8depicts a block diagram of the sensor chip 11B.

As depicted in FIG. 7, the sensor chip 11B has a stacked structure inwhich a sensor substrate 51 on which a pixel array section 12 is formedand a logic substrate 52 on which a global controlling circuit 13 isformed are stacked. Further, the sensor chip 11B has such a connectionstructure that, in a peripheral region of the sensor chip 11B in whichit does not overlap with the pixel array section 12 as viewed in plan,control lines 21 of the sensor substrate 51 and the global controllingcircuit 13 of the logic substrate 52 are connected to each other. Inparticular, in the example depicted in FIG. 7, in the sensor chip 11B, aplurality of control lines 21 disposed along a column direction of thesensor elements disposed in a matrix in the pixel array section 12 areconnected to the global controlling circuit 13 side on the upper side ofthe sensor substrate 51.

Accordingly, in the sensor chip 11B, a global controlling signaloutputted from the global controlling circuit 13 is supplied to thesensor elements of the pixel array section 12 from the upper side of thesensor substrate 51 as indicated by a void arrow mark in FIG. 7. At thistime, the global controlling circuit 13 is configured such that it isdisposed such that the longitudinal direction thereof extends along along side of the pixel array section 12 and the sensor chip 11B has theshortest distance from the global controlling circuit 13B to the sensorelements of the pixel array section 12.

A configuration of the sensor chip 11B is described further withreference to FIG. 8.

The sensor substrate 51 has a pixel array section 12 and TSV (ThroughSilicon Via) regions 53-1 to 53-3 disposed thereon. The logic substrate52 has a global controlling circuit 13, a rolling controlling circuit14, a column ADC 15, a logic circuit 17 and TSV regions 54-1 to 54-3disposed thereon. For example, in the sensor chip 11B, a sensor signaloutputted from each sensor element of the pixel array section 12 is ADconverted by the column ADC 15 and is subjected to various signalprocesses by the logic circuit 17, whereafter it is outputted to theoutside.

The TSV regions 53-1 to 53-3 and the TSV regions 54-1 to 54-3 areregions in which through-electrodes for electrically connecting thesensor substrate 51 and the logic substrate 52 to each other are formed,and a through electrode is disposed for each control line 21.Accordingly, the TSV regions 53-1 to 53-3 and the TSV regions 54-1 to54-3 are disposed such that they overlap with each other when the sensorsubstrate 51 and the logic substrate 52 are stacked. It is to be notedthat not only through electrodes can be used for connection in the TSVregions 54, but also, for example, micro bump or copper (Cu—Cu)connection can be utilized.

According to the sensor chip 11B configured in this manner, the wiringline length of the control line 21 can be made short by the layout inwhich the global controlling circuit 13 is disposed so as to extendalong a long side of the pixel array section 12 similarly to the sensorchip 11 of FIG. 1. Accordingly, the sensor chip 11B can perform controlfor the sensor elements at a higher speed similarly to the sensor chip11 of FIG. 1.

FIG. 9 is a block diagram depicting a first modification of the sensorchip 11B depicted in FIG. 8. It is to be noted that, from among blocksconfiguring the sensor chip 11B-a depicted in FIG. 9, components commonto those of the sensor chip 11B of FIG. 8 are denoted by like referencecharacters, and detailed description of them is omitted.

As depicted in FIG. 9, in particular, the sensor chip 11B-a isconfigured commonly to the sensor chip 11B of FIG. 8 in that it has sucha stacked structure that the sensor substrate 51 on which the pixelarray section 12 is formed and the logic substrate 52 on which theglobal controlling circuit 13 is formed are stacked.

On the other hand, the sensor chip 11B-a is different in configurationfrom the sensor chip 11B of FIG. 8 in that the two global controllingcircuits 13-1 and 13-2 are disposed on the logic substrate 52 so as toextend along the upper side and the lower side of the pixel arraysection 12, respectively, and two control lines 21-1 and 21-2 aredisposed such that they are separate from each other at the center ofthe columns of the sensor elements disposed in a matrix on the pixelarray section 12.

In particular, in the sensor chip 11B-a, the driving element 32-1 isconnected to an upper end of the control line 21-1 and the drivingelement 32-2 is connected to the lower end of the control line 21-2similarly as in the sensor chip 11-b depicted in FIG. 5. Accordingly,the sensor chip 11B-a is configured such that, to the sensor elementsdisposed on the upper side with respect to the center of the pixel arraysection 12, the driving element 32-1 included in the global controllingcircuit 13-1 supplies a global controlling signal from the upper end ofthe control line 21-1. Further, the sensor chip 11B-a is configured suchthat, to the sensor elements disposed on the lower side with respect tothe center of the pixel array section 12, the driving element 32-2included in the global controlling circuit 13-2 supplies a globalcontrolling signal from the lower end of the control line 21-2.

In the sensor chip 11B-a configured in such a manner as described above,the distance from the driving element 32-1 to a sensor element disposedat the remote end (in the example of FIG. 9, at the lower end) of thecontrol line 21-1 and the distance from the driving element 32-2 to asensor element disposed at the remote end (in the example of FIG. 9, atthe upper end) of the control line 21-2 can be made shorter, forexample, than that in the sensor chip 11B of FIG. 8. Consequently, thesensor chip 11B-a can perform control for the sensor elements at ahigher speed because the delay amount and the slew rate occurring withglobal signals outputted from the global controlling circuits 13-1 and13-2 can be further reduced.

FIG. 10 is a block diagram depicting a second modification of the sensorchip 11B depicted in FIG. 8. It is to be noted that, from among blocksconfiguring the sensor chip 11B-b depicted in FIG. 10, components commonto those of the sensor chip 11B of FIG. 8 are denoted by like referencecharacters, and detailed description of them is omitted.

In particular, as depicted in FIG. 10, the sensor chip 11B-b is commonin configuration to the sensor chip 11B of FIG. 8 in that it has astacked structure in which a sensor substrate 51 on which a pixel arraysection 12 is formed and a logic substrate 52 on which a globalcontrolling circuit 13 is formed are stacked.

On the other hand, the sensor chip 11B-b is different in configurationfrom the sensor chip 11B of FIG. 8 in that two global controllingcircuits 13-1 and 13-2 are disposed on the logic substrate 52 so as toextend along the upper side and the lower side of the pixel arraysection 12, respectively, and driving elements 32-1 and 32-2 areconnected to the opposite ends of a control line 21.

In particular, in the sensor chip 11B-b, the driving element 32-1included in the global controlling circuit 13-1 supplies a globalcontrolling signal from the upper end of the control line 21 and thedriving element 32-2 included in the global controlling circuit 13-2supplies a global controlling signal from the lower end of the controlline 21 similarly to the sensor chip 11-a depicted in FIG. 4.

The sensor chip 11B-b configured in this manner can suppress a skewbetween the two driving element 32-1 and driving element 32-2 and caneliminate a dispersion in delay time that occurs in a global controllingsignal propagated along the control line 21. Consequently, in the sensorchip 11B-b, control for the sensor elements can be performed at a higherspeed. It is to be noted that, in the sensor chip 11B-b, it is necessaryto perform the control such that the delay difference in outputting ofglobal controlling signals is avoided from becoming great such thatthrough current may not be generated.

In the sensor chip 11B configured in such a manner as described above,control for the sensor elements in the stacked structure in which thesensor substrate 51 and the logic substrate 52 are stacked can beperformed at a higher speed similarly as in the sensor chip 11 of FIG.1.

It is to be noted that, in the configuration examples depicted in FIGS.8 to 10, the column ADC 15 is configured such that sensor signal is readout from the lower end side of the pixel array section 12 through theTSV region 53-3 and the TSV region 54-3 disposed on the lower side. Inaddition to such a configuration as just described, for example, twocolumn ADCs 15 are disposed in the proximity of the upper and lowersides and configured such that a sensor signal is read out from theupper end side and the lower end side of the pixel array section 12 bythe two column ADCs 15.

<Fourth Configuration Example of Sensor Chip>

A fourth embodiment of a sensor chip to which the present technology isapplied is described with reference to FIG. 11. It is to be noted that,from among blocks configuring the sensor chip 11C depicted in FIG. 11,components common to those of the sensor chip 11B of FIG. 8 are denotedby like reference characters, and detailed description of them isomitted.

In particular, as depicted in FIG. 11, the sensor chip 11C is common inconfiguration to the sensor chip 11B of FIG. 8 in that it has a stackedstructure in which a sensor substrate 51 on which a pixel array section12 is formed and a logic substrate 52 on which a global controllingcircuit 13 is formed are stacked.

On the other hand, the sensor chip 11C is different in configurationfrom the sensor chip 11B of FIG. 8 in that a pixel array section 12C hasa vertically elongated rectangular region similarly to the pixel arraysection 12A of the sensor chip 11A depicted in FIG. 6. Accordingly, inthe sensor chip 11C, the global controlling circuit 13C is disposed onthe left side of the logic substrate 52 so as to extend along a longside of the pixel array section 12C. With this, a control line 21C isdisposed toward the leftward and rightward direction of the pixel arraysection 12C for each row of the sensor elements disposed in a matrix inthe pixel array section 12C.

Further, in the sensor chip 11C, a rolling controlling circuit 14C isdisposed on the right side of the logic substrate 52 (side opposing tothe global controlling circuit 13C) so as to extend along a long side ofthe pixel array section 12C. It is to be noted that, although the globalcontrolling circuit 13C and the pixel array section 12C may be disposedon the same side with respect to the logic substrate 52, in this case,since it is supposed that the wiring line length of any one of thembecomes longer, it is preferable to adopt such arrangement as depictedin FIG. 11.

Furthermore, in the sensor chip 11C, the column ADC 15C is disposed onthe lower side of the logic substrate 52 so as to extend along a shortside of the pixel array section 12C. The reason why the column ADC 15Cis disposed in a direction orthogonal to the rolling controlling circuit14C in this manner is that it is necessary to turn on the sensorelements connected to one AD converter one by one, and such a layoutthat individual wiring lines overlap with each other is avoided.

According to the sensor chip 11C configured in this manner, the wiringline length of the control line 21C can be reduced by the layout inwhich the global controlling circuit 13C is disposed so as to extendalong a long side of the pixel array section 12C similarly to the sensorchip 11B of FIG. 8. Accordingly, the sensor chip 11C can perform controlfor the sensor elements at a higher speed similarly to the sensor chip11B of FIG. 8.

<Fifth Configuration Example of Sensor Chip>

A fifth embodiment of a sensor chip to which the present technology isapplied is described with reference to FIG. 12. It is to be noted that,from among blocks configuring the sensor chip 11D depicted in FIG. 12,components common to those of the sensor chip 11B of FIG. 8 are denotedby like reference characters, and detailed description of them isomitted.

In particular, as depicted in FIG. 12, the sensor chip 11D is common inconfiguration to the sensor chip 11B of FIG. 8 in that it has a stackedstructure in which a sensor substrate 51 on which a pixel array section12 is formed and a logic substrate 52 on which a global controllingcircuit 13 is formed are stacked.

On the other hand, the sensor chip 11D is different in configurationfrom the sensor chip 11B of FIG. 8 in that, a plurality of column ADCs15, in the example of FIG. 12, ADCs 15-1 to 15-12, are disposedcorresponding to a region of the sensor substrate 51, in which the pixelarray section 12 is formed, are disposed on the logic substrate 52.

For example, the sensor chip 11D is configured such that an ADC 15 isdisposed for each predetermined region of the pixel array section 12. Inthe case where the 12 ADCs 15-1 to 15-12 are used as depicted in FIG.12, an ADC 15 is disposed for each of 12 divisional regions into whichthe pixel array section 12 is divided equally, and AD conversion ofsensor signals outputted from the sensor elements provided in theindividual regions is performed in parallel. It is to be noted that, inaddition to the configuration in which an ADC 15 is disposed for each ofpredetermined regions of the pixel array section 12, for example, aconfiguration in which one ADC 15 is disposed for each of sensorelements included in the pixel array section 12 may be applied.

According to the sensor chip 11D configured in this manner, the wiringline length of the control line 21 can be made short by the layout inwhich the global controlling circuit 13 is disposed so as to extendalong a long side of the pixel array section 12 similarly to the sensorchip 11B of FIG. 8. Accordingly, the sensor chip 11D can perform controlfor the sensor elements at a higher speed similarly to the sensor chip11B of FIG. 8.

Further, in the sensor chip 11D, restriction of the positionalrelationship between the rolling controlling circuit 14 and the columnADC 15 to such constraints to the column ADC 15 depicted in FIG. 8 iseliminated. For example, although, in the sensor chip 11D depicted inFIG. 12, the rolling controlling circuit 14 is disposed on the rightside of the logic substrate 52, the rolling controlling circuit 14 maybe disposed on any of the upper side and the lower side. In other words,the rolling controlling circuit 14 may be disposed at any place if thereis no restriction in regard to the location of the pixel array section12 with respect to the sensor chip 11D (for example, the center positionof the sensor chip 11D with respect to the optical center).

As an alternative, for example, in the case where there is a strongrestriction to the optical center and the center position of the sensorchip 11D, the layout can be balanced well by disposing the rollingcontrolling circuit 14 at a position on the opposite side to the regionin which the column ADC 15 is disposed with respect to the globalcontrolling circuit 13. This makes it possible to improve thecharacteristic of the sensor chip 11D.

<Sixth Configuration Example of Sensor Chip>

A sixth embodiment of a sensor chip to which the present technology isapplied is described with reference to FIGS. 13 to 22. It is to be notedthat, from among blocks configuring the sensor chip 11E depicted inFIGS. 13 to 22, components common to those of the sensor chip 11B ofFIGS. 7 and 8 are denoted by like reference characters, and detaileddescription of them is omitted.

As depicted in FIG. 13, the sensor chip 11E has a stacked structure inwhich a sensor substrate 51 on which a pixel array section 12 is formedand a logic substrate 52 on which a global controlling circuit 13 isformed are stacked similarly to the sensor chip 11B depicted in FIG. 7.Further, the sensor chip 11E has such a connection structure that theglobal controlling circuit 13 is disposed such that it overlaps with thecenter of the pixel array section 12 when the sensor chip 11E is viewedin plan and the global controlling circuit 13 is connected to thecontrol line 21 at the central portion of the pixel array section 12.

For example, in the case where the sensor chip 11E is connectable at thepixel array section 12 by interconnection of copper (Cu) configuringwiring lines, connection utilizing micro bumps or TSVs or likeconnection, the distance from the driving element 32 to a sensor elementdisposed at the remote end of the control line 21 can be made short.

A configuration of the sensor chip 11E is further described withreference to FIG. 14.

As depicted in FIG. 14, in the sensor substrate 51, the pixel arraysection 12 is a horizontally elongated rectangular region having longsides extending in the horizontal direction and short sides extending inthe vertical direction. Accordingly, on the logic substrate 52, theglobal controlling circuit 13 is disposed such that the longitudinaldirection thereof extends along a long side of the pixel array section12. Further, the global controlling circuit 13 is disposed substantiallyat the center of the logic substrate 52 such that a wiring line foroutputting from the driving element 32 of the global controlling circuit13 is connected to the center of a control line 21 disposed toward theupward and downward direction of the pixel array section 12. It is to benoted that such a configuration may be used that a wiring line foroutputting from the driving element 32 extends through the substratefrom the global controlling circuit 13 directly toward the pixel arraysection 12.

In the sensor chip 11E configured in this manner, the distances from thedriving element 32 to sensor elements at the opposite ends of thecontrol line 21 can be made short. Accordingly, since the delay amountand the slew rate of a global controlling signal can be improved, thesensor chip 11E can perform control for the sensor elements at a higherspeed.

Further, such a configuration as indicated by the sensor chip 11E ispreferable for application, for example, to a ToF sensor.

FIG. 15 is a block diagram depicting a first modification of the sensorchip 11E depicted in FIG. 14. It is to be noted that, from among blocksconfiguring the sensor chip 11E-a depicted in FIG. 15, components commonto those of the sensor chip 11E of FIG. 14 are denoted by like referencecharacters, and detailed description of them is omitted.

In particular, as depicted in FIG. 15, the sensor chip 11E-a is commonin configuration to the sensor chip 11E of FIG. 14 in that it has astacked structure in which a sensor substrate 51 on which a pixel arraysection 12 is formed and a logic substrate 52 on which a globalcontrolling circuit 13 is formed are stacked.

On the other hand, on the sensor substrate 51, the sensor chip 11E-a isdifferent in configuration from the sensor chip 11E of FIG. 14 in thattwo control lines 21-1 and 21-2 divided at the center are disposed forone row of sensor elements disposed in a matrix in the pixel arraysection 12. Further, the sensor chip 11E-a is different in configurationfrom the sensor chip 11E of FIG. 14 in that the global controllingcircuit 13 on the logic substrate 52 includes two driving elements 32-1and 32-2 for one row of the sensor elements.

Further, the sensor chip 11E-a has such a connection structure that thedriving element 32-1 is connected to a center side end portion of thecontrol line 21-1 and the driving element 32-2 is connected to a centerside end portion of the control line 21-2. In particular, the sensorchip 11E-a is configured such that, from among a plurality of sensorelements disposed on one row of the pixel array section 12, the sensorelements disposed on the upper side with respect to the center aredriven by the driving element 32-1 through the control line 21-1, andthe sensor elements disposed on the lower side with respect to thecenter are driven by the driving element 32-2 through the control line21-2.

According to the sensor chip 11E-a configured in this manner, thedistance from the driving element 32-1 to a sensor element disposed atthe remote end of the control line 21-1 and the distance from thedriving element 32-2 to a sensor element disposed at the remote end ofthe control line 21-2 can be made short similarly to the sensor chip 11Eof FIG. 14. Accordingly, the sensor chip 11E-a can improve the delayamount and the slew rate of a global controlling signal similarly to thesensor chip 11E of FIG. 14.

Further, in the sensor chip 11E-a, since the load per one drivingelement 32 can be reduced, the size of the driving element 32 can bereduced from that of the sensor chip 11E of FIG. 14. Furthermore, wherethe sensor chip 11E-a is configured such that two driving elements 32are disposed for one column of sensor elements, the layout of thedriving elements 32 is integrated to one place, and the overall layoutstructure can be simplified.

FIG. 16 is a block diagram depicting a second modification of the sensorchip 11E depicted in FIG. 14. It is to be noted that, from among blocksconfiguring the sensor chip 11E-b depicted in FIG. 16, components commonto those of the sensor chip 11E of FIG. 14 are denoted by like referencecharacters, and detailed description of them is omitted.

In particular, the sensor chip 11E-b depicted in FIG. 16 is common inconfiguration to the sensor chip 11E of FIG. 14 in that it has a stackedstructure in which a sensor substrate 51 on which a pixel array section12 is formed and a logic substrate 52 on which a global controllingcircuit 13 is formed are stacked.

On the other hand, the sensor chip 11E-b is different in configurationfrom the sensor chip 11E of FIG. 14 in that, on the sensor substrate 51,two control lines 21-1 and 21-2 separate at the center are disposed forone row of sensor elements disposed in a matrix in the pixel arraysection 12. Further, the sensor chip 11E-b is different in configurationfrom the sensor chip 11E of FIG. 14 in that, on the logic substrate 52,two global controlling circuits 13-1 and 13-2 are disposed.

Further, the sensor chip 11E-b has such a connection structure that thedriving element 32-1 is connected to the center of the control line 21-1and the driving element 32-2 is connected to the center of the controlline 21-2. In particular, the sensor chip 11E-b is configured such that,from among a plurality of sensor elements disposed in one row of thepixel array section 12, the sensor elements disposed on the upper sidewith respect to the center are driven by the driving element 32-1through the control line 21-1 and the sensor elements disposed on thelower side with respect to the center are driven by the driving element32-2 through the control line 21-2.

In the sensor chip 11E-b configured in this manner, the distance fromthe driving element 32-1 to a sensor element disposed at the remote endof the control line 21-1 and the distance from the driving element 32-2to a sensor element disposed at the remote end of the control line 21-2can be made shorter in comparison with the sensor chip 11E of FIG. 14.Consequently, the sensor chip 11E-b can achieve driving at a higherspeed than the sensor chip 11E of FIG. 14 and can achieve furtherimprovement of the delay amount and the slew rate of a globalcontrolling signal.

Further, as depicted in FIG. 16, in the sensor chip 11E-b, since theglobal controlling circuits 13-1 and 13-2 can be disposed divisionally,the logic circuit 17 can be disposed at a central location between them.It is to be noted that, though not depicted, the column ADC 15 may bedisposed at a central location between the global controlling circuits13-1 and 13-2.

Further, such a configuration as indicated by the sensor chip 11E-b issuitable for application, for example, to a ToF sensor.

FIG. 17 is a block diagram depicting a third modification of the sensorchip 11E depicted in FIG. 14. It is to be noted that, from among blocksconfiguring the sensor chip 11E-c depicted in FIG. 17, components commonto those of the sensor chip 11E of FIG. 14 are denoted by like referencecharacters, and detailed description of them is omitted.

In particular, the sensor chip 11E-c depicted in FIG. 17 is common inconfiguration to the sensor chip 11E of FIG. 14 in that it has a stackedstructure in which a sensor substrate 51 on which a pixel array section12 is formed and a logic substrate 52 on which a global controllingcircuit 13 is formed are stacked.

On the other hand, the sensor chip 11E-c is different in configurationfrom the sensor chip 11E of FIG. 14 in that, on the sensor substrate 51,two control lines 21-1 and 21-2 divided at the center are disposed forone row of sensor elements disposed in a matrix in the pixel arraysection 12. Further, the sensor chip 11E-c is different in configurationfrom the sensor chip 11E of FIG. 14 in that two global controllingcircuits 13-1 and 13-2 are disposed on the logic substrate 52.

Further, the sensor chip 11E-c has such a connection structure that thedriving element 32-1 is connected to the center of the control line 21-1and the driving element 32-2 is connected to the center of the controlline 21-2 similarly to the sensor chip 11E-b of FIG. 16. Accordingly,the sensor chip 11E-c can achieve driving at a higher speed than thesensor chip 11E of FIG. 14 and can achieve further improvement of thedelay amount and the slew rate of a global controlling signal incomparison with the sensor chip 11E of FIG. 14 similarly to the sensorchip 11E-b of FIG. 16.

Further, in the sensor chip 11E-c, the column ADC 15-1 is disposed onthe upper side of the logic substrate 52 and the column ADC 15-2 isdisposed on the lower side of the logic substrate 52. In the sensor chip11E-c configured in this manner, since it has a structure in which thelayout thereof is symmetrical upwardly and downwardly, it is improved insymmetry, and consequently, the sensor chip 11E-c can be improved incharacteristic.

FIG. 18 is a block diagram depicting a fourth modification of the sensorblock 11E depicted in FIG. 14. It is to be noted that, from among blocksconfiguring the sensor chip 11E-d depicted in FIG. 18, components commonto those of the sensor chip 11E of FIG. 14 are denoted by like referencecharacters, and detailed description of them is omitted.

In particular, the sensor chip 11E-d depicted in FIG. 18 is common inconfiguration to the sensor chip 11E of FIG. 14 in that it has a stackedstructure in which a sensor substrate 51 on which a pixel array section12 is formed and a logic substrate 52 on which a global controllingcircuit 13 is formed are stacked.

On the other hand, the sensor chip 11E-d is different in configurationfrom the sensor chip 11E of FIG. 14 in that, on the logic substrate 52,two global controlling circuits 13-1 and 13-2 are disposed and that thesensor chip 11E-d has such a connection structure that the globalcontrolling circuit 13-1 is connected to a substantially center of anupper half of the control line 21 and the global controlling circuit13-2 is connected to a substantially center of a lower half of thecontrol line 21. In other words, the sensor chip 11E-d is configuredsuch that it uses a single control line 21 to which the control lines21-1 and 21-2 of FIG. 17 are connected.

The sensor chip 11E-d configured in this manner can suppress a skewbetween the two driving element 32-1 and driving element 32-2 and caneliminate a dispersion in delay time that occurs in a global controllingsignal propagated along the control line 21. Consequently, in the sensorchip 11E-d, control for the sensor elements can be performed at a higherspeed. It is to be noted that, in the sensor chip 11E-d, it is necessaryto perform the control such that the delay difference in outputting ofglobal controlling signals is avoided from becoming great such thatthrough current may not be generated.

FIG. 19 is a block diagram depicting a fifth modification of the sensorblock 11E depicted in FIG. 14. It is to be noted that, from among blocksconfiguring the sensor chip 11E-e depicted in FIG. 19, components commonto those of the sensor chip 11E of FIG. 14 are denoted by like referencecharacters, and detailed description of them is omitted. Further, in thesensor chip 11E-e depicted in FIG. 19, in order to avoid theillustration from becoming complicated, illustration of part of blocksconfiguring the sensor chip 11E-e is omitted.

In particular, the sensor chip 11E-e depicted in FIG. 19 is common inconfiguration to the sensor chip 11E of FIG. 14 in that it has a stackedstructure in which a sensor substrate 51 on which a pixel array section12 is formed and a logic substrate 52 on which a global controllingcircuit 13 is formed are stacked.

On the other hand, the sensor chip 11E-e is different in configurationfrom the sensor chip 11E of FIG. 14 in that, on the sensor substrate 51,four divisional control lines 21-1 to 21-4 are disposed for one row ofsensor elements disposed in a matrix in the pixel array section 12.Further, the sensor chip 11E-e is different in configuration from thesensor chip 11E of FIG. 14 in that, on the logic substrate 52, fourglobal controlling circuits 13-1 to 13-4 are disposed.

Further, the sensor chip 11E-e has such a connection configuration thatdriving elements 32-1 to 32-4 of the global controlling circuits 13-1 to13-4 are connected to central points of the control lines 21-1 to 21-4,respectively. Accordingly, in the sensor chip 11E-e, the distance fromthe driving elements 32-1 to 32-4 to sensor elements disposed at theremote end of the respective control lines 21-1 to 21-4 can be furtherreduced. Consequently, the sensor chip 11E-e can achieve furtherincrease in speed of control for the sensor elements. It is to be notedthat, although it is supposed that the column ADC 15A, logic circuit 17and so forth are disposed separately, also in such a case as justdescribed, it is necessary to adopt a layout in which this does not havean influence on a characteristic.

It is to be noted that, although the configuration example depicted inFIG. 19 is described using the four divisional control lines 21-1 to21-4, the control line 21 may otherwise be divided into three controllines or five or more control lines. Thus, such a configuration can betaken that, to substantially central portions of the divisional controllines 21, respectively corresponding global controlling circuits 13 areconnected.

FIG. 20 is a block diagram depicting a sixth modification of the sensorblock 11E depicted in FIG. 14. It is to be noted that, from among blocksconfiguring the sensor chip 11E-f depicted in FIG. 20, components commonto those of the sensor chip 11E of FIG. 14 are denoted by like referencecharacters, and detailed description of them is omitted.

In particular, the sensor chip 11E-f depicted in FIG. 20 is common inconfiguration to the sensor chip 11E of FIG. 14 in that it has a stackedstructure in which a sensor substrate 51 on which a pixel array section12 is formed and a logic substrate 52 on which a global controllingcircuit 13 is formed are stacked.

On the other hand, the sensor chip 11E-f is different in configurationfrom the sensor chip 11E of FIG. 14 in that four global controllingcircuits 13-1 to 13-4 are disposed on the logic substrate 52 and globalcontrolling circuits 13-1 to 13-4 are connected at equal distances tothe control line 21. In other words, the sensor chip 11E-d is configuredsuch that it uses a single control line 21 to which the control lines21-1 to 21-4 of FIG. 19 are connected.

The sensor chip 11E-f configured in this manner can suppress a skewamong the four driving elements 32-1 to 32-4 and can eliminate adispersion in delay time that occurs in a global controlling signalpropagated along the control line 21. Consequently, in the sensor chip11E-f, control for the sensor elements can be performed at a higherspeed. It is to be noted that, in the sensor chip 11E-f, it is necessaryto perform the control such that the delay difference in outputting ofglobal controlling signals becomes great such that through current maynot be generated.

FIG. 21 is a block diagram depicting a seventh modification of thesensor block 11E depicted in FIG. 14. It is to be noted that, from amongblocks configuring the sensor chip 11E-g depicted in FIG. 21, componentscommon to those of the sensor chip 11E-e of FIG. 19 are denoted by likereference characters, and detailed description of them is omitted.

In particular, the sensor chip 11E-g is configured including a singleglobal controlling circuit 13 and is configured including buffercircuits 55-1 to 55-3 in place of the global controlling circuits 13-2to 13-4 of the sensor chip 11E-e of FIG. 19. The buffer circuits 55-1 to55-3 have buffers 56-1 to 56-3, respectively, and an output of thedriving element 32 of the global controlling circuit 13 is branched bythe buffers 56-1 to 56-3 and connected to four divisional control lines21-1 to 21-4.

Also with the sensor chip 11E-g configured in this manner, furtherincrease in speed of control for the sensor elements can be achievedsimilarly with the sensor chip 11E-e of FIG. 19.

FIG. 22 is a block diagram depicting an eighth modification of thesensor block 11E depicted in FIG. 14. It is to be noted that, from amongblocks configuring the sensor chip 11E-h depicted in FIG. 22, componentscommon to those of the sensor chip 11E-f of FIG. 20 are denoted by likereference characters, and detailed description of them is omitted.

In particular, the sensor chip 11E-g is configured including a singleglobal controlling circuit 13 and is configured including buffercircuits 55-1 to 55-3 in place of the global controlling circuits 13-2to 13-4 of the sensor chip 11E-f of FIG. 20. The buffer circuits 55-1 to55-3 have buffers 56-1 to 56-3, respectively, and an output of thedriving element 32 of the global controlling circuit 13 is branched bythe buffers 56-1 to 56-3 and connected to a control line 21.

Also with the sensor chip 11E-h configured in this manner, furtherincrease in speed of control for the sensor elements can be achievedsimilarly with the sensor chip 11E-f of FIG. 20.

<Seventh Configuration Example of Sensor Chip>

A seventh embodiment of a sensor chip to which the present technology isapplied is described with reference to FIGS. 23 to 25. It is to be notedthat, from among blocks configuring the sensor chip 11F depicted inFIGS. 23 to 25, components common to those of the sensor chip 11E ofFIG. 13 are denoted by like reference characters, and detaileddescription of them is omitted.

In particular, the sensor chip 11F depicted in FIG. 23 has a stackedstructure in which a sensor substrate 51 and two logic substrates 52-1and 52-2 are stacked. In other words, the present technology can beapplied to a structure in which three semiconductor substrates arestacked.

As depicted in FIG. 23, the sensor chip 11F is configured such that apixel array section 12 is formed on a sensor substrate 51 of the firstlayer and a global controlling circuit 13 and memories 61-1 and 61-2 areformed on a logic substrate 52-1 of the second layer while, for example,a column ADC 15, a logic circuit 17 and forth not depicted are formed ona logic substrate 52-2 of the third layer.

Also in the sensor chip 11F configured in this manner, by disposing theglobal controlling circuit 13 on the logic substrate 52-1 along thelongitudinal direction of the pixel array section 12 of the sensorsubstrate 51, control for the sensor elements can be performed at ahigher speed similarly as in the sensor chip 11E of FIG. 13.

Further, in the sensor chip 11F in which the sensor substrate 51, logicsubstrate 52-1 and logic substrate 52-2 are slacked in this order,preferably the global controlling circuit 13 is disposed at the centerof the logic substrate 52-1 stacked between the sensor substrate 51 andthe logic substrate 52-2. Consequently, the distance from the globalcontrolling circuit 13 to a sensor element disposed at the remote end ofthe logic substrate 52-1 can be made short. Naturally, if the distancefrom the global controlling circuit 13 to a sensor element disposed atthe remote end of the control line 21 can be made short, then the layoutis not limited to such a layout as depicted in FIG. 23.

FIG. 24 is a perspective view depicting a first modification of thesensor chip 11F depicted in FIG. 23.

As depicted in FIG. 24, the sensor chip 11F-a is configured such thatthe pixel array section 12 is formed on the sensor substrate 51 of thefirst layer; the memories 61-1 and 61-2 are formed on the logicsubstrate 52-1 of the second layer; and, for example, the globalcontrolling circuit 13, the column ADC 15 and logic circuit 17 notdepicted and so forth are formed on the logic substrate 52-2 of thethird layer.

Also in the sensor chip 11F-a configured in this manner, by disposingthe global controlling circuit 13 on the logic substrate 52-2 so as toextend along the longitudinal direction of the pixel array section 12 ofthe sensor substrate 51, control for the sensor elements can beperformed at a higher speed similarly as in the sensor chip 11E of FIG.13.

FIG. 25 is a perspective view depicting a second modification of thesensor chip 11F depicted in FIG. 23.

As depicted in FIG. 25, the sensor chip 11F-b is configured such thatthe pixel array section 12 is formed on the sensor substrate 51 of thefirst layer; the memory 61 is formed on the logic substrate 52-1 of thesecond layer; and, for example, the global controlling circuit 13, thecolumn ADC 15 and logic circuit 17 not depicted and so forth are formedon the logic substrate 52-2 of the third layer. It is to be noted thatthe sensor chip 11F-b has such a connection configuration that thecontrol line 21 is connected to the global controlling circuit 13utilizing a TSV region formed in a peripheral region of the sensor chip11F-b, for example, similarly to the sensor chip 11B of FIG. 8.

Also in the sensor chip 11F-b configured in this manner, by disposingthe global controlling circuit 13 on the logic substrate 52-2 so as toextend along the longitudinal direction of the pixel array section 12 ofthe sensor substrate 51, control for the sensor elements can beperformed at a higher speed similarly as in the sensor chip 11E of FIG.13.

It is to be noted that, for example, three or more semiconductorsubstrates may be stacked, and a global controlling circuit 13 may bedisposed at two locations as described hereinabove with reference toFIG. 16 or a global controlling circuit 13 may be disposed at aplurality of locations equal to or greater than two locations. In thiscase, a semiconductor substrate on which the memory 61 is disposed, thelocation or divisional number of the memory 61 can be laid out suitablyin response to the disposition of the global controlling circuit 13.

For example, such a configuration may be adopted that the pixel arraysection 12 is disposed on a semiconductor substrate of the first layer;the column ADC 15, logic circuit 17 and so forth are disposed on asemiconductor substrate of the second layer; and the memory 61 isdisposed on a semiconductor substrate of the third layer. Also in such aconfiguration as just described, by disposing the global controllingcircuit 13 on the semiconductor substrate of the second layer, thewiring line length can be made short. However, the global controllingcircuit 13 may otherwise be disposed on a semiconductor substrate onwhich the memory 61 is disposed.

<Eighth Configuration Example of Sensor Chip>

An eighth embodiment of a sensor chip to which the present technology isapplied is described with reference to FIG. 26. It is to be noted that,from among blocks configuring the sensor chip 11G depicted in FIG. 26,components common to those of the sensor chip 11E of FIG. 14 are denotedby like reference characters, and detailed description of them isomitted.

In particular, the disposition of the global controlling circuit 13 inthe sensor chip 11 is not limited to those in the embodiments describedhereinabove, and such various layouts as depicted in FIG. 26 can beadopted. Naturally, in any disposition, such a layout that is notdepicted may be adopted if the global controlling circuit 13 is disposedso as to extend along a long side of the pixel array section 12.

As depicted in FIG. 26A, a sensor chip 11G has such a layout that thepixel array section 12 and the global controlling circuit 13 aredisposed on the sensor substrate 51 and the rolling controlling circuit14, column ADC 15 and logic circuit 17 are disposed on the logicsubstrate 52. Further, in the sensor chip 11G, the global controllingcircuit 13 is disposed on the lower side of the pixel array section 12so as to extend along a long side of the pixel array section 12.

As depicted in FIG. 26B, a sensor chip 11G-a has such a layout that thepixel array section 12 and the global controlling circuit 13 aredisposed on the sensor substrate 51 and the rolling controlling circuit14, column ADC 15 and logic circuit 17 are disposed on the logicsubstrate 52. Further, in the sensor chip 11G-a, the global controllingcircuit 13 is disposed on the upper side of the pixel array section 12so as to extend along a long side of the pixel array section 12.

As depicted in FIG. 26C, a sensor chip 11G-b has such a layout that thepixel array section 12 and the global controlling circuits 13-1 and 13-2are disposed on the sensor substrate 51 and the rolling controllingcircuit 14, column ADC 15 and logic circuit 17 are disposed on the logicsubstrate 52. Further, in the sensor chip 11G-b, the global controllingcircuits 13-1 and 13-2 are disposed on the upper side and the lower sideof the pixel array section 12 so as to extend along a long side of thepixel array section 12, respectively.

As depicted in FIG. 26D, a sensor chip 11G-c has such a layout that thepixel array section 12 and the global controlling circuits 13-1 and 13-2are disposed on the sensor substrate 51 and the rolling controllingcircuit 14, column ADC 15 and logic circuit 17 are disposed on the logicsubstrate 52. Further, in the sensor chip 11G-c, the global controllingcircuits 13-1 and 13-2 are disposed on the upper side and the lower sideof the pixel array section 12 so as to extend along a long side of thepixel array section 12, respectively, and the two control lines 21-1 and21-2 are disposed such that they are separate at the center of a columnof the sensor elements disposed in a matrix on the pixel array section12.

As depicted in FIG. 26E, a sensor chip 11G-d has such a layout that thepixel array section 12 and the global controlling circuits 13-1 and 13-2are disposed on the sensor substrate 51 and the rolling controllingcircuit 14, column ADC 15 and logic circuit 17 are disposed on the logicsubstrate 52. Further, in the sensor chip 11G-d, the inputting andoutputting section 16 is disposed on the logic substrate 52 so as toextend along a long side of the pixel array section 12.

For example, the sensor chip 11G-d is configured such that it suppliespower from the inputting and outputting section 16 to the globalcontrolling circuit 13 through the TSV region 54-1 and the TSV region53-1. It is to be noted that, in addition to utilization of a TSV,interconnection of copper (Cu) configuring wiring lines, micro bumps andso forth may be utilized to supply power to the global controllingcircuit 13. Further, for the wiring line for supplying power to theglobal controlling circuit 13, a same connection method as that for thecontrol line 21 may be used or a connection method of some othercombination may be used. Further, in addition to the configuration inwhich semiconductor substrates of two layers are stacked, also in aconfiguration in which semiconductor substrates of three layers arestacked, preferably the global controlling circuit 13 is disposed in theproximity of the inputting and outputting section 16 similarly.

It is to be noted that, while the various layouts depicted in FIG. 26indicate exampled in which the column ADC 15 is disposed on one side ofthe logic substrate 52, a layout in which the column ADC 15 is disposedon the opposite upper and lower sides of the logic substrate 52 may beadopted. Further, the position of the column ADC 15 or the logic circuit17 is not restricted to such disposition as depicted in FIG. 26.

As described above, by applying a stacked structure to the sensor chip11, the global controlling circuit 13 can be disposed in variouslayouts, which increases the degree of freedom in layout and increasesthe effect of controlling the global controlling circuit 13 and therolling controlling circuit 14 individually.

<Configuration Example of Distance Image Sensor>

FIG. 27 is a block diagram depicting a configuration example of adistance image sensor that is an electronic apparatus utilizing thesensor chip 11.

As depicted in FIG. 27, the distance image sensor 201 is configuredincluding an optical system 202, a sensor chip 203, an image processingcircuit 204, a monitor 205 and a memory 206. Thus, the distance imagesensor 201 can acquire a distance image according to the distance of animaging object by receiving light (modulated light or pulse light)projected from a light source apparatus 211 toward the imaging objectand reflected by the surface of the imaging object.

The optical system 202 is configured having one or a plurality of lensesand introduces image light (incident light) from an imaging object tothe sensor chip 203 such that an image is formed on a light receptionface (sensor section) of the sensor chip 203.

As the sensor chip 203, the sensor chip 11 of the embodiments describedhereinabove is applied, and a distance signal indicative of a distancedetermined from a reception signal (APD OUT) outputted from the sensorchip 203 is supplied to the image processing circuit 204.

The image processing circuit 204 performs image processing forconstructing a distance image on the basis of a distance signal suppliedfrom the sensor chip 203, and a distance image (image data) obtained bythe imaging processing is supplied to and displayed on the monitor 205or supplied to and stored (recorded) into the memory 206.

In the distance image sensor 201 configured in this manner, by applyingthe sensor chip 11 described above, for example, a more accuratedistance image can be acquired by performance of higher speed control.

[1.3. Particular Configuration Examples of Distance Image Sensor]

In a ToF camera system that adopts the indirect system, light isirradiated in the form of pulses, and a pulse generator for generatingsuch pulses is provided. An existing pulse generator makes a phase by ashift register after division. Accordingly, a phase resolution isdetermined by a division setting. For example, if a signal of afrequency of 800 MHz is divided by eight, then only eight phases can bemade. Further, in an existing pulse generator, steps of division orphase that can be made are limited to multiples of two. Accordingly, itis not possible to obtain a phase of 36 degrees by division by ten.Preferably, a ToF camera system that adopts the indirect system canperform wide setting in order to adaptively change the frequency by arange. Further, although it is necessary for an existing pulse generatorto change the frequency of a PLL in order to perform fine setting, ifthe frequency of the PLL is changed, then time is required before thefrequency is stabilized (it is necessary to weight for response time).

Further, an existing pulse generator is great in number of flip-flopsand is low in area efficiency. For example, a 32-divider requires 32flip-flops, and also a shift register of 32 steps requires 32flip-flops. Accordingly, a pulse generator configured from adivide-by-32 divider and a shift register of 32 steps requires 64flip-flops.

Thus, taking the foregoing into consideration, the discloser of thepresent case has conducted an intensive study about the technology of apulse generator that is used in a ToF camera system that especiallyadopts the indirect system and can be ready for various settings for afrequency or a phase with a simple configuration. As a result, thediscloser of the present case has invented a pulse generator that isused in a ToF camera system that especially adopts the indirect systemand can be ready for various settings for a frequency or a phase whileit is simple in configuration.

Now, a configuration example used in a ToF camera system that especiallyadopts the indirect system according to an embodiment of the presentdisclosure is described. FIG. 28 is an explanatory view depicting afunctional configuration example of the pulse generator 300 according tothe embodiment of the present disclosure. The pulse generator 300depicted in FIG. 28 is, for example, a pulse generator provided in thedistance image sensor 201 depicted in FIG. 27. In the following, thefunctional configuration example of the pulse generator 300 according tothe embodiment of the present disclosure is described with reference toFIG. 28.

As depicted in FIG. 28, the pulse generator 300 according to theembodiment of the present disclosure is configured including counters310 and 340, a D-type flip-flog 320 and an AND gate 330.

The counter 310 is a programmable counter that counts clocks inputted tothe pulse generator 300, for example, clocks generated by a PLL. Thecounter 310 is a counter for setting a phase and is, for example, acounter that adds a value at the timing of a rising edge of a clockinputted thereto. A phase setting is sent from the outside of the pulsegenerator 300 to the counter 310. An output of the counter 310 is sentto an input of the D-type flip-flog 320.

The D-type flip-flog 320 uses an output of the counter 310 as a clock CKthereto and outputs a value of an input D from an output Q on the basisof the clock CK. The output of the D-type flip-flog 320 is sent to theAND gate 330.

The AND gate 330 logically ANDs (AND) a clock inputted to the pulsegenerator 300 and an output of the D-type flip-flog 320, and outputs aresult of the ANDing to the counter 340.

The counter 340 is a programmable counter that counts output clocks ofthe AND gate 330. The counter 340 is a counter for setting division andis, for example, a counter that adds a value at the timing of a risingedge of a clock inputted thereto.

A counter used as the counters 310 and 340 may be any counter if it is aprogrammable counter. Constituent factors of a programmable counter arethat the counter is a multi-bit counter, that the counter receives dataof multi bits as an input, that the counter includes a comparatorbetween input data and a count value and so forth. As such counter, apulse swallow counter, a pulse follower counter, a binary counter, agray code counter, a Johnson counter and so forth are applicable.

FIG. 29 is an explanatory view depicting a waveform example of a signalinputted to the pulse generator 300, signals generated in the inside ofthe pulse generator 300 and a signal outputted from the pulse generator300.

Referring to FIG. 29, “Clock” indicates a clock inputted to the pulsegenerator 300, and “Counter (phase)” indicates a count value by thecounter 310. “1stCNO” indicates an output of the D-type flip-flog 320,and “2stCNI” indicates an output of the AND gate 330. “Counter(division)” indicates a count value by the counter 340, and “OUT”indicates an output of the counter 340.

In the example depicted in FIG. 29, the output of the D-type flip-flog320 switches from low to high when the count value of the counter 310becomes “6.” Further, when the count value by the counter 340 becomes“8,” the output of the counter 340 switches from low to high or fromhigh to low. In particular, the phase and the frequency of a clock to beoutputted from the pulse generator 300 can be adjusted by changing thesettings of the counters 310 and 340.

By using the clock outputted from the pulse generator 300 for driving ofa light source and driving of pixels of a sensor chip, the drivingtiming of the light source and the driving timing of the pixels of thesensor chip can be adjusted flexibly. For example, it is possible to set2⁸ as the phase setting and set 2⁸ as the division setting. In thiscase, the number of flip-flops is eight for each counter and is totaling16 for the implementation. Accordingly, in comparison with aconventional pulse generator that requires 64 flip-flops, the pulsegenerator according to the embodiment of the present disclosure cansignificantly reduce the circuit scale.

It is to be noted that, while, in the pulse generator 300 depicted inFIG. 28, the counter 340 for setting a frequency is provided in the nextstage to the counter 310 for setting a phase, the present disclosure isnot limited to such an example as just described. In the pulse generator300 according to the present embodiment, a counter for setting a phasemay be provided in the stage next to a counter for setting a frequency.

FIG. 30 is an explanatory view depicting a schematic configurationexample of a distance image sensor that uses the pulse generatoraccording to the embodiment of the present disclosure. In FIG. 30, pulsegenerators 300 a and 300 b, a PLL 350, a light source driver 352, alight source 354, a pixel modulation driver 356 and a pixel 358 aredepicted. The pixel 358 is a one-tap pixel in which one pixel includesone transistor.

A clock MCK outputted from the PLL 350 is sent to the pulse generators300 a and 300 b. Further, to the pulse generator 300 a, a phase settingfor the light source 354 is inputted, and to the pulse generator 300 b,a phase setting for the pixel 358 is inputted. In particular, in orderto set a phase difference between a signal outputted from the pulsegenerator 300 a (light source outputting signal) and a signal outputtedfrom the pulse generator 300 b (pixel modulation signal), individuallyunique phase settings are inputted to the pulse generators 300 a and 300b. Further, a common modulation frequency setting is inputted to thepulse generators 300 a and 300 b. Consequently, pulses of a samefrequency are outputted from the pulse generators 300 a and 300 b.

FIG. 31 is an explanatory view depicting an example of signals outputtedfrom the pulse generators 300 a and 300 b and phase settings inputted tothe pulse generators 300 a and 300 b. In the example depicted in FIG.31, a light source phase setting inputted to the pulse generator 300 ais a setting by which, when the count value of the counter 310 a becomes“6,” the output of the D-type flip-flop 320 a switches from low to high.Further, in the example depicted in FIG. 31, the pixel phase settinginputted to the pulse generator 300 b is a setting by which, when thecount value of the counter 310 b becomes “9,” the output of the D-typeflip-flog 320 b switches from low to high. By such settings, the phasedifference between the light source outputting signal outputted from thepulse generator 300 a and the pixel modulation signal outputted from thepulse generator 300 b can be set to 90 degrees.

Another example is described. FIG. 32 is an explanatory view depicting aschematic configuration example of a distance image sensor that uses thepulse generator according to the embodiment of the present disclosure.In FIG. 32, pulse generators 300 a and 300 b, a PLL 350, a light sourcedriver 352, a light source 354, an inverter 355, pixel modulationdrivers 356 a and 356 b and a pixel 358′ are depicted. The pixel 358′ isa two-tap pixel in which two transistors are provided in one pixel andis configured such that a signal from the pulse generator 300 b isinputted to the transistors.

In the example depicted in FIG. 32, in order to set a phase differencebetween a signal to be outputted from the pulse generator 300 a (lightsource outputting signal) and a signal to be outputted from the pulsegenerator 300 b (pixel modulation signal), individually unique phasesettings are inputted to the pulse generators 300 a and 300 b similarlyas in the example depicted in FIG. 30. Further, to the pulse generators300 a and 300 b, a common modulation frequency setting is inputted.Further, in the example depicted in FIG. 32, the output of the pulsegenerator 300 b is branched into two, one of which is outputted as it isto the pixel modulation driver 356 a and the other of which is invertedby the inverter 355 and then outputted to the pixel modulation driver356 b. Consequently, from an output signal from the pulse generator 300b, two signals having phases different by 180 degrees from each other(pixel modulation signals A and B) are generated.

FIG. 33 is an explanatory view depicting an example of signals outputtedfrom the pulse generators 300 a and 300 b and phase settings inputted tothe pulse generators 300 a and 300 b. In the example depicted in FIG.33, the light source phase setting inputted to the pulse generator 300 ais a setting by which, when the count value of the counter 310 a becomes“6,” the output of the D-type flip-flop 320 a switches from low to high.Further, in the example depicted in FIG. 33, the pixel phase settinginputted to the pulse generator 300 b is a setting by which, when thecount value of the counter 310 b becomes “9,” the output of the D-typeflip-flop 320 b switches from low to high. By such settings, the phasedifference between the light source outputting signal to be outputtedfrom the pulse generator 300 a and the pixel modulation signal A to beoutputted from the pulse generator 300 b can be set to 90 degrees. Then,since the output of the pulse generator 300 b is branched into two andone of the two branch outputs is inverted by the inverter 355 and thenoutputted to the pixel modulation driver 356 b, the phase differencebetween the pixel modulation signal A and the pixel modulation signal Bcan be set to 180 degrees.

A different example is described. FIG. 34 is an explanatory viewdepicting a schematic configuration example of a distance image sensorthat uses the pulse generated according to the embodiment of the presentdisclosure. In FIG. 34, pulse generators 300 a, 300 b and 300 c, a PLL350, a light source driver 352, a light source 354, pixel modulationdrivers 356 a and 356 b and a pixel 358′. The pixel 358′ is a two-tappixel in which two transistors are provided in one pixel and isconfigured such that signals from the pulse generator 300 b are inputtedto the transistors.

The example depicted in FIG. 34 is not different from the configurationexample depicted in FIG. 32 in that a signal from the pulse generator300 a (light source outputting signal) is outputted to the light source354. On the other hand, the example depicted in FIG. 34 is differentfrom the configuration example depicted in FIG. 34 in that a signal tobe outputted from the pixel 358′ is generated by the pulse generators300 b and 300 c. In particular, in order to set the phase differenceamong a signal to be outputted from the pulse generator 300 a (lightsource outputting signal), a signal to be outputted from the pulsegenerator 300 b (pixel modulation signal A) and a signal to be outputtedfrom the pulse generator 300 c (pixel modulation signal B), individuallyunique phase settings are inputted to the pulse generators 300 a, 300 band 300 c.

FIG. 35 is an explanatory view depicting an example of signals outputtedfrom the pulse generators 300 a, 300 b and 300 c and phase settingsinputted to the pulse generators 300 a and 300 b. In the exampledepicted in FIG. 35, the light source phase setting to be inputted tothe pulse generator 300 a is a setting by which, when the count value ofthe counter 310 a becomes “6,” the output of the D-type flip-flop 320 aswitches from low to high. Further, in the example depicted in FIG. 35,the pixel phase setting to be inputted to the pulse generator 300 b is asetting by which, when the count value of the counter 310 b becomes “9,”the output of the D-type flip-flop 320 b switches from low to high.Further, in the example depicted in FIG. 35, the pixel phase setting tobe inputted to the pulse generator 300 c is a setting by which, when thecount value of the counter 310 c becomes “15,” the output of the D-typeflip-flop 320 c switches from low to high. By such settings, the phasedifference between the light source outputting signal to be outputtedfrom the pulse generator 300 a and the pixel modulation signal A to beoutputted from the pulse generator 300 b can be set to 90 degrees.Further, the phase difference between the light source outputting signalto be outputted from the pulse generator 300 a and the pixel modulationsignal B to be outputted from the pulse generator 300 c can be set to270 degrees.

By the configuration in which the pixel phase settings are inputted tothe pulse generators in this manner, a system delay can be corrected.The system delay here is a delay of time after a pixel modulation signalis outputted from a pulse generator until the pixel modulation signal isactually inputted to a pixel. FIG. 36 is an explanatory view depictingan example of a signal outputted from a pulse generator and a phasesetting inputted to the pulse generator. As depicted in FIG. 36, byproviding an offset to a pixel phase setting to be inputted to a pulsegenerator for a pixel, the offset can be added to the pixel modulationsignal without changing the setting of the pixel phase setting to beinputted to a pulse generator for a light source. In other words, byadjusting at least any one of the pulse generator for a light source orthe pulse generator for a pixel, calibration for synchronizing a lightsource driver and a pixel modulation driver with each other can beachieved.

A distance image sensor that includes the pulse generator according tothe present embodiment makes operation in a high frequency, for example,in a frequency of, for example, approximately 100 MHz, possible. Anexisting distance image sensor of the ToF system operates with a lowfrequency of, for example, approximately 20 MHz. In the case ofoperation of approximately 20 MHz, even if a displacement of two tothree nsec or the like exists between driving of a light source anddriving of a pixel, the influence of the displacement is small. However,in the case of operation of approximately 100 MHz, if a displacement bytwo nsec occurs, then this makes a loss of 25% and the influence of thisis large. Since a distance image sensor that includes the pulsegenerator according to the present embodiment allows unique setting of alight source phase setting and a pixel phase setting, calibration forsynchronizing a light source driver and a pixel modulation driverbecomes possible by adjusting at least any one of the pulse generatorfor a light source or the pulse generator for a pixel as describedabove.

Subsequently, a distance image sensor of the ToF system that can set theduty of a light source to an arbitrary value is described. As describedabove, the pulse generator 300 generates a light source outputtingsignal having a duty of 50%. FIG. 37 is an explanatory view depicting anexample of a waveform of a light source outputting signal generated bythe pulse generator 300 and having a duty of 50%.

However, if light is emitted on the basis of the light source outputtingsignal whose duty is 50%, then a cyclic error based on a distancemeasurement principle (continuous method) occurs, and a distancemeasurement error can be caused by this cyclic error. FIG. 38 is anexplanatory view depicting a manner in which a distance measurementerror is caused by a cyclic error. The upper stage indicates a manner inthe case where the waveform of light emitted from the light source is asine wave, and the lower stage indicates a manner in the case where thewaveform of light emitted from the light source is a square wave. In thegraphs, the axis of abscissa indicates the delay amount such that, whenthe value of the delay amount is 100, the delay amount is 360 degrees.In the continuous method, calculation is performed assuming that thesignal is an ideal sine wave. In the case where light is emitted inaccordance with a light source outputting signal of a sine wave, nodistortion occurs with the phase delay amount as in the case of thegraph on the upper right side. On the other hand, in the case wherelight is emitted in accordance with a light source outputting signal ofa square wave, some distortion occurs with the phase delay amount as inthe case of the graph on the lower right side. This distortion directlymakes a cause of degrading the linearity of distance measurement.Although an existing distance image sensor deals with this cause bycorrecting the distortion by software, since the error by a cyclic errorincreases as the distance increases in distance measurement, theinfluence of the distortion increases.

Therefore, the discloser of the present case has conducted an intensivestudy about the technology that is used in a ToF camera system thatespecially adopts the indirect system and can reduce the distancemeasurement error by a cyclic error with a simple configuration. As aresult, the discloser of the present case has invented a technology thatis used in a ToF camera system that especially adopts the indirectsystem and can reduce the distance measurement error by a cyclic errorwith a simple configuration.

The distance image sensor according to the present embodiment reducesthe cyclic error by changing the duty of the light source outputtingsignal, particularly by decreasing the duty of the light sourceoutputting signal to less than 50%. To this end, the distance imagesensor according to the present embodiment includes a pulse generatorthat generates a light source outputting signal whose duty is decreasedto less than 50%. FIG. 39 is an explanatory view depicting an example ofwaveforms of light source outputting signals having duties of 30% and25% less than 50%.

A configuration for outputting light source outputting signals havingduties of 30% and 25% less than 50% in this manner is described. FIG. 40is an explanatory view depicting a configuration example for outputtinga light source outputting signal in the distance image sensor accordingto the embodiment of the present disclosure. In FIG. 40, pulsegenerators 300 a and 300 b, an AND gate 410 for ANDing (logicallyANDing) with an output of the pulse generator 300 a and an output of thepulse generator 300 b after the output of the pulse generator 300 ainverted, and a selector 420 are depicted. Both of the pulse generators300 a and 300 b generate a signal for causing a light source to emitlight.

The pulse generator 300 a is a pulse generator for the object ofgenerating a light source outputting signal whose duty is 50%.Meanwhile, the pulse generator 300 b is a pulse generator for the objectof adjusting the phase setting to generate a light source outputtingsignal whose duty is made less than 50% by the combination of a signalgenerated by the pulse generator 300 a and a signal generated by thepulse generator 300 b.

FIG. 41 is an explanatory view depicting an overview of generation of alight source outputting signal whose duty is made less than 50%. “MAIN”in FIG. 41 depicts an example of a waveform of a signal generated by thepulse generator 300 a, and “SUB” depicts an example of a waveform of asignal generated by the pulse generator 300 a. Further, “LSR” depicts anexample of a waveform of a light source outputting signal whose duty ismade less than 50% by the combination of the signal generated by thepulse generator 300 a and the signal generated by the pulse generator300 b.

As depicted in FIG. 41, the waveform of the signal generated by thepulse generator 300 a and the waveform of the signal generated by thepulse generator 300 a have a phase difference therebetween. If, in thisstate, the signal generated by the pulse generator 300 a is, afterinverted, ANDed with the signal generated by the pulse generator 300 b,then it is possible to generate a light source outputting signal whoseduty is made less than 50% like “LSR.”

The selector 420 selects and outputs any one of the output of the pulsegenerator 300 a and the output of the AND gate 410. To the selector 420,a mode switching signal is supplied, and the selector 420 selects andoutputs any one of the output of the pulse generator 300 a, namely, asignal whose duty is 50%, and the output of the AND gate 410, namely, asignal whose duty is less than 50%, in response to the substance of themode switching signal.

Where the distance image sensor of the ToF system according to theembodiment of the present disclosure has the configuration depicted inFIG. 40, it can cause the light source to emit light with differentduties. Further, the distance image sensor of the ToF system accordingto the embodiment of the present disclosure can reduce the cyclic errorby changing the duty of a light source outputting signal, particularly,by reducing the duty to less than 50%.

FIG. 42 is an explanatory view depicting an example of light sourcephase settings to be set to the pulse generators 300 a and 300 b. Asdepicted in FIG. 42, a phase difference can be provided between thewaveform (LSR) of a signal generated by the pulse generator 300 a andthe waveform (LSR_SUB) generated by the pulse generator 300 a by makingthe light source phase setting to be set to the pulse generator 300 aand the light source phase setting to be set to the pulse generator 300b different from each other. Further, if the signal generated by thepulse generator 300 a is logically ANDed, after the waveform thereof isinverted, with the signal generated by the pulse generator 300 b, thenit is possible to generate a light source outputting signal whose dutyis made smaller than 50% like “LSR OUT.”

Naturally, the phase of the signal generated by the pulse generator 300b may be advanced from the phase of the signal generated by the pulsegenerator 300 a. FIG. 43 is an explanatory view depicting a waveformexample of signals generated by the pulse generators 300 a and 300 b andlight source outputting signals generated on the basis of the signalsgenerated by the pulse generators 300 a and 300 b.

By switching and selecting signals of different duties to make lightsource outputting signals in this manner, for example, it is possible tocause a light source to emit light whose frequency is made differentbetween a case in which the distance to an object at a long distance ismeasured and another case in which the distance to an object at a shortdistance is measured and make the duty smaller than 50% to reduce thecyclic error.

It is to be noted that, although the present example demonstrates anexample in which the duty of a light source outputting signal isselected from between 50% and less than 50%, the present disclosure isnot limited to such an example as just described.

FIG. 44 is an explanatory view depicting a driving example of a distanceimage sensor of the ToF system according to the embodiment of thepresent disclosure. What is depicted in FIG. 44 is an example in whichthe frequency and the duty of light emitted from a light source is madedifferent between distance measurement of an object at a long distanceand distance measurement of an object at a short distance.

In the example depicted in FIG. 44, upon distance measurement of anobject at a long distance, light is emitted at a duty of 32% at afrequency of 20 MHz, but upon distance measurement of an object at ashort distance, light is emitted at a duty of 32% at a frequency of 80MHz. Then, in the example depicted in FIG. 44, in the distancemeasurement of the object at the long distance and the distancemeasurement of the object at the short distance, measurement isperformed in the four phases of zero degrees, 90 degrees, 180 degreesand 270 degrees.

The distance image sensor of the ToF system according to the embodimentof the present disclosure can reduce the cyclic error by causing a lightsource to emit light in this manner.

FIG. 45 is a flow chart depicting an operation example of the distanceimage sensor of the ToF system according to the embodiment of thepresent disclosure. The distance image sensor decides whether or not anobject of a distance measurement target is at a long distance (longdistance equal to or longer than a predetermined distance) (step S101).If the object is at a long distance, then the distance image sensorcarries out distance measurement with a low frequency (step S102) andgenerates a depth map at the long distance (step S103). In this distancemeasurement, the distance image sensor causes the light source to emitlight at a duty of less than 50%. Then, the distance image sensorestimates (arithmetically operates) the position of the object of thedistance measurement target on the basis of the depth map at the longdistance (step S104).

On the other hand, if the object of the distance measurement target isat a short distance, then the distance image sensor carries out distancemeasurement with a high frequency (step S105) and generates a depth mapat the short distance (step S106). In this distance measurement, thedistance image sensor causes the light source to emit light at a dutyless than 50%. Then, the distance image sensor estimates (arithmeticallyoperates) the position of the object of the distance measurement on thebasis of the depth map at the short distance (step S107).

In this manner, the distance image sensor of the ToF system according tothe embodiment of the present disclosure can cause, when it causes lightto be emitted from the light source, the light source to emit light at aduty different depending upon the setting. Thereupon, by causing thelight source to emit light at a duty less than 50%, the distance imagesensor of the ToF system according to the embodiment of the presentdisclosure can reduce the influence of the cyclic error and increase theaccuracy in distance measurement.

Subsequently, a distance image sensor of the ToF system that performsdistance measurement by changing the setting of a modulation frequencyin a single frame is described.

In a distance image sensor of the indirect ToF system, the modulationfrequency and the distance measurement error have an inverseproportional relationship therebetween. Although it is necessary toincrease the modulation frequency in order to increase the accuracy toperform measurement, if the modulation frequency is increased, then thedistance measurement range is reduced.

In an existing distance image sensor of the indirect ToF system, in thecase where two different modulation frequencies are used to performdistance measurement, change of the setting of the modulation frequencyis permitted only in cycles for accumulation into pixels and for readingout of the accumulated data. Therefore, in the case where distancemeasurement is performed using two different modulation frequencies,since frames necessary for depth calculation increases, the time untildistance measurement completion increases. Further, if it is tried tochange the setting of the modulation frequency during an accumulationperiod, then the dead time during setting transition becomes long andthe ratio of invalid signals increases.

FIG. 46 is an explanatory view depicting an operation example of adistance image sensor of the indirect ToF system when distancemeasurement is performed using a same modulation frequency during anaccumulation period in a single frame. In the example of FIG. 46, anexample is depicted in which distance measurement is performed while thephase is changed at a modulation frequency of 60 MHz and thenmeasurement is performed while the phase is changed at a modulationfrequency of 20 MHz. In this case, in the case where the frequency is tobe changed, although it is necessary to change the setting of the PLL, aperiod for stabilization of the PLL becomes required, and it isdifficult to change the frequency immediately. Accordingly, time isrequired for switching of the modulation frequency, and the time beforedistance measurement completion becomes long.

FIG. 47 is an explanatory view depicting an operation example of adistance image sensor of the indirect ToF system when distancemeasurement is performed using a same modulation frequency during anaccumulation period in one frame. In the example of FIG. 47, an exampleis depicted in which, where one cycle includes distance measurement witha modulation frequency of 60 MHz and distance measurement with amodulation frequency of 20 MHz, distance measurement is performed whilethe phase is changed after one cycle comes to an end. In this case, timeis required for switching of the modulation frequency, and the timebefore distance measurement completion becomes long. Further, also inregard to a reading out time number from pixels, eight times of readingout are required before distance measurement completion similarly as inthe example depicted in FIG. 46.

Therefore, in the present embodiment, a distance image sensor of theindirect ToF system is demonstrated in which such a pulse generator inwhich two programmable counters are combined is used to change thesetting of the modulation frequency in a short period of time during anaccumulation period in a single frame and such change of the setting canbe reflected. It is to be noted that the term frame designates a periodafter accumulation of the image sensor is started until reading out ofthe image sensor is completed.

FIG. 48 is an explanatory view depicting a driving example of a distanceimage sensor of the indirect ToF system according to the embodiment ofthe present disclosure. In the present embodiment, during anaccumulation period in a single frame, driving with the modulationfrequencies of 60 MHz and 20 MHz is executed and results of the drivingare acquired by a single time reading out operation from pixels. Bydriving with different modulation frequencies from each other during anaccumulation period in a single frame in this manner, the distance imagesensor of the indirect ToF system according to the embodiment of thepresent disclosure can reduce the reading out time number. Further, thedistance image sensor of the indirect ToF system according to theembodiment of the present disclosure can save the reading out time andcan improve the frame rate. It is to be noted that, although dead timeoccurs at a timing at which the setting of the modulation frequency ischanged, the period of the dead time is very short in comparison withthe period for the stabilization of the PLL described hereinabove.

FIG. 49 is an explanatory view depicting a particular example of drivingof a distance image sensor of the indirect ToF system according to theembodiment of the present disclosure. In FIG. 49, an example is depictedin which, as the settings to the pulse generator 300 described above,two different settings are provided for each of the frequency setting,pixel phase setting and light source position setting. The reason whytwo kinds of phase setting are provided is that, if the modulationfrequency changes, then also the setting of the phase changes naturally.

FIG. 49 further depicts a trigger signal for setting change. In theexample of FIG. 49, in the case where the trigger is low, the modulationfrequency is set to 60 MHz, and in the case where the trigger is high,the modulation frequency is set to 40 MHz. In other words, the settingto the pulse generator 300 switches depending upon the state of thetrigger signal for setting change. Thereupon, if the pulse generator 300detects that the state of the trigger signal for setting change haschanged, then the pulse generator 300 resets the value of the counterand outputs a pulse based on the setting after the change. In the lowerstage of FIG. 49, a manner is depicted in which the frequency of thepixel modulation signal and the light source outputting signal changesin response to a change of the trigger signal for setting change.

FIG. 50 is an explanatory view depicting an example of a configurationused in a distance image sensor of the indirect ToF system according tothe embodiment of the present disclosure. In FIG. 50, a counter 340 forsetting a modulation frequency, a PLL 350 that outputs a clock, a timingcontroller 341 that receives an output of the counter 340 as asynchronizing signal and a selector 342 for outputting the setting tothe counter 340 are depicted.

The timing controller 341 detects a change of the state of the settingchange trigger signal. If the timing controller 341 detects that thestate of the setting change trigger signal has changed, then it outputsa switch signal to the selector 342 and outputs a rest signal forresetting the counter value to the counter 340 in order to switch thedivision setting. The selector 342 selects and outputs one of the twodivision settings on the basis of the switch signal from the timingcontroller 341.

For example, it is assumed that the timing controller 341 detects that,when the counter 340 is operating with the division setting 1, the stateof the setting change trigger signal has changed. The timing controller341 latches a setting change trigger signal with a synchronizing signalin the inside thereof and outputs a switch signal and a reset signalwithin a period within which the modulation signal is low. The selector342 receiving the switch signal switches the output to the counter 340from the division setting 1 to a division setting 2. Then, the counter340 resets the counter value on the basis of the reset signal and startscounting with the division setting 2 to output a modulation signal onthe basis of the division setting 2.

The present embodiment can provide a distance image sensor of theindirect ToF system that can change the setting of a modulationfrequency in short time during an accumulation period of a single frameusing a pulse generator that is a combination of two programmablecounters and reflect the change of the setting as described above. Bychanging the setting of the modulation frequency in short time during anaccumulation period in a single frame and reflecting the change of thesetting, the distance image sensor of the indirect ToF system accordingto the embodiment of the present disclosure can reduce the reading outtime number before distance measurement completion and reduction of thepower consumption can be anticipated. Further, the distance image sensorof the indirect ToF system according to the embodiment of the presentdisclosure can complete distance measurement in a short period of timein comparison with that in an alternative case in which the setting ofthe modulation frequency is changed by changing the setting of the PLL.If a plurality of PLLs are provided, then although it is possible alsoto change the setting of the modulation frequency by switching betweenthe PLLs, the provision of a plurality of PLLs leads to increase of thecircuit scale. It is possible for the distance image sensor of theindirect ToF system according to the embodiment of the presentdisclosure to change the setting of the modulation frequency withoutincreasing the circuit scale.

Since the distance image sensor of the indirect ToF system according tothe embodiment of the present disclosure has such a configuration asdepicted in FIG. 50, it can change the modulation frequency of the pixelmodulation signal and the light source outputting signal by a change ofthe trigger signal for setting change. Further, the distance imagesensor of the indirect ToF system according to the embodiment of thepresent disclosure can be driven with different modulation frequenciesduring an accumulation period in a single frame.

Subsequently, a distance image sensor of the indirect ToF system foravoiding erroneous distance measurement when a plurality of camerasmeasure the distance to a same target is described.

In an active distance measurement system, light is emitted from a lightsource and light reflected by an object of the distance measurementtarget is detected to perform distance measurement to the distancemeasurement target. In this active distance measurement system, if aplurality of cameras measure the distance to a same target, then signalsof them mix up, which gives rise to erroneous distance measurement. FIG.51 is an explanatory view depicting a manner in which light isirradiated from a plurality of light sources to a same distancemeasurement target and a certain image sensor receives the light fromthe plurality of light sources. Although originally it is desirable forthe image sensor depicted in FIG. 51 to operate so as to receive lightfrom a light source A, also it possibly occurs that the image sensorreceives light from a different light source B. FIG. 52 is anexplanatory view depicting a manner in which light emission time(modulation time) overlaps between the light source A and the lightsource B. If the light emission time overlaps between the light source Aand the light source B in this manner, then the image sensor receiveslight from different light sources at the same time, which gives rise tocontamination.

In the case where the distance to a same target is to be measured by aplurality of cameras in accordance with the active distance measurementsystem, a technique for decreasing the probability of such overlap byusing a random number in the time direction for a light emission timingseems available. FIG. 53 is an explanatory view depicting a manner inwhich the light emission timings are displaced from each other at randombetween the light source A and the light source B. However, even if thelight emission timings are displaced at random, it is difficult to fullyprevent the overlap.

Therefore, in the present embodiment, the phase is inverted by 180degrees using a toggle signal generated pseudo-randomly as a trigger toencrypt the modulation for interference prevention. Since, to a distanceimage sensor of the indirect ToF system according to the presentembodiment, a modulation pattern of light to be received by an imagesensor is known in advance, light modulated in a pattern different fromthe pattern can be handled as an invalid signal that does not contributeto distance measurement.

FIG. 54 is an explanatory view depicting an example of a pixelmodulation signal that can be used by a distance image sensor of theindirect ToF system according to the present embodiment and is anexplanatory view depicting an example in which the phase of the pixelmodulation signal is inverted by 180 degrees at a timing of transitionof the state of a pulse based on a bit generated pseudo-randomly(pseudo-random pulse). The pseudo-random pulse is low when thepseudo-randomly generated bit is zero but is high when thepseudo-randomly generated bit is one. In FIG. 54, the phase of the pixelmodulation signal transits by 180 degrees at a timing at which thepseudo-random pulse transits from low to high or from high to low. Thedistance image sensor of the indirect ToF system according to thepresent embodiment can avoid use of light based on a pulse whose statechanges in a different pattern in distance measurement by using thepseudo-random pulse in generation of a modulation signal.

FIG. 55 is an explanatory view illustrating generation of apseudo-random pulse used in the present embodiment. FIG. 55 depicts acase in which light reception and reading out are performed four timesin one frame. In regard to variables depicted in FIG. 55, N indicates apseudo-random pattern length, L indicates an encoding cycle length ofthe modulation signal, and M indicates a cycle in which a pseudo-randompulse is normalized with a logic frequency. The variable N has a bitlength of 15 bits, and L can take one of the values of 4, 8, 16 and 32.Further, the variable M has a bit length of 9 bits. For example, if itis assumed that the modulation frequency is 60 MHz, then N=3, L=8 andL=16.

The pseudo-random pulse is generated, for example, in the inside of thesensor chip 11 described hereinabove. For example, the pseudo-randompulse can be generated by the logic circuit 17.

FIG. 56 is an explanatory view depicting an example of a pseudo-randompulse (PSKTRIG) generated on the basis of a bit generatedpseudo-randomly and a signal (MIX signal) having a phase inverted by 180degrees from the pseudo-random pulse by state transition of thepseudo-random pulse. In the example of FIG. 56, during one time readingout, the phase of the modulation signal is changed by state transitionof the pseudo-random pulse based on a pseudo-randomly generated bit of11 bits.

Subsequently, a configuration for inverting the phase of a modulationsignal by state transition of the pseudo-random pulse. FIG. 57 is anexplanatory view depicting a configuration example used in a distanceimage sensor of the indirect ToF system according to the embodiment ofthe present disclosure. In FIG. 57, pulse generators 300 a, 300 b and300 d, a PLL 350 and a pulse edge detection circuit 360 are depicted.The pulse generator 300 a is a pulse generator that outputs a lightsource modulation signal. The pulse generator 300 b is a pulse generatorthat outputs a pixel modulation signal. The pulse generator 300 d is apulse generator that outputs a reference pulse.

The reference pulse outputted from the pulse generator 300 d is sent tothe pulse edge detection circuit 360. Also a pseudo-random pulse is sentto the pulse edge detection circuit 360. The pulse edge detectioncircuit 360 detects that state transition of the pseudo-random pulse hasoccurred by detecting an edge of the pulse. Then, when the pulse edgedetection circuit 360 detects that state transition of the pseudo-randompulse has occurred, it outputs a phase inversion signal for invertingthe phase of signals to be outputted from the pulse generators 300 a and300 b to selectors 370 a and 370 b.

If a phase inversion signal is not sent from the pulse edge detectioncircuit 360, then the selectors 370 a and 370 b output signals outputtedfrom the pulse generators 300 a and 300 b as they are. If a phaseinversion signal is sent from the pulse edge detection circuit 360, thenthe selectors 370 a and 370 b output signals after the phase of thesignals outputted from the pulse generators 300 a and 300 b is invertedby inverters 371 a and 371 b.

FIG. 58 is an explanatory view depicting an example in which the phaseof a modulation signal changes on the basis of state transition of thepseudo-random pulse. In the case where the state of the pseudo-randompulse is low, the modulation signal is a signal (zero deg signal) of aphase same as that of the reference pulse. If the state of thepseudo-random pulse changes to high, then the phase of the modulationsignal is inverted at a timing at which the state of the reference pulseimmediately after then transits. Thereafter, if the state of thepseudo-random pulse changes to low, then the phase of the modulationsignal changes at a timing at which the state of the reference pulsechanges immediately after then.

FIG. 59 is an explanatory view depicting an example in which the phaseof the modulation signal changes on the basis of state transition of thepseudo-random pulse. The signals depicted in FIG. 59 are, in order fromabove, a pseudo-random pulse, a non-encrypted signal of zero degrees ofa duty of 50%, an encrypted signal of zero degrees of a duty of 50%, anon-encrypted signal of zero degrees of a duty of 25%, an encryptedsignal of zero degrees of a duty of 25%, non-encrypted signal of 90degrees of a duty of 50%, an encrypted signal of 90 degrees of a duty of50%, a non-encrypted signal of 90 degrees of a duty of 25%, and anencrypted signal of 90 degrees of a duty of 25%.

As described hereinabove, the distance image sensor of the indirect ToFsystem according to the embodiment of the present disclosure can changethe duty of a pulse to be generated by the pulse generator 300.Especially, by setting the duty of the light source outputting signalsmaller than 50%, the cyclic error can be reduced. Accordingly, in theFIG. 59, by using the signal of a 50% duty as a pixel modulation signaland using a signal of a 25% duty as a light source outputting signal,while the distance image sensor of the indirect ToF system according tothe embodiment of the present disclosure reduces the cyclic error, itcan decide light to be used for distance measurement even in the casewhere the image sensor receives light from a plurality of light sources.

The distance image sensor of the indirect ToF system according to theembodiment of the present disclosure synchronizes the timings at whichthe phases of the pixel modulation signal and light source outputtingsignal are shifted with each other as depicted in FIG. 59. Bysynchronizing the timings at which the phases of the pixel modulationsignal and the light source outputting signal are shifted with eachother, it can decide light to be used for distance measurement even inthe case where the image sensor receives light from a plurality of lightsources.

FIG. 60 is an explanatory view depicting an example in which the phaseof the modulation signal changes based on state transition of thepseudo-random pulse. The signals depicted in FIG. 60 are, in order fromabove, a non-encrypted modulation signal, a pseudo-random pulse, a pixelmodulation signal A, a pixel modulation signal B, a light sourceoutputting signal of a phase same as that of the non-encryptedmodulation signal, a non-encrypted modulation signal, a pseudo-randompulse, a pixel modulation signal A, a pixel modulation signal B and alight source outputting signal having a phase displaced by 90 degreesfrom that of the non-encrypted modulation signal. The duty of the lightsource outputting signal depicted in FIG. 60 is 50%.

FIG. 61 is an explanatory view depicting another example in which thephase of the modulation signal changes based on state transition of thepseudo-random pulse. The signals depicted in FIG. 61 are, in order fromabove, a non-encrypted modulation signal, a pseudo-random pulse, a pixelmodulation signal A, a pixel modulation signal B, a light sourceoutputting signal of a phase same as that of the non-encryptedmodulation signal, a non-encrypted modulation signal, a pseudo-randompulse, a pixel modulation signal A, a pixel modulation signal B and alight source outputting signal having a phase displaced by 90 degreesfrom that of the non-encrypted modulation signal. The duty of the lightsource outputting signal depicted in FIG. 61 is 50%.

FIG. 62 is an explanatory view depicting an example of a configurationthat selects and outputs two kinds of signals having different dutyratios from each other from the two pulse generators 300 a and 300 b. Asdescribed hereinabove, by making the phases of signals of the pulsegenerators 300 a and 300 b different from each other, a signal having aduty smaller than 50% can be generated. Thereupon, one of a signal whoseduty is 50% and a signal whose duty is smaller than 50% is outputted asa light source outputting signal depending upon the state of a signalDUTYON.

FIG. 63 depicts an example of a waveform of a signal LSR having a dutysmaller than 50% and a signal LSR_PSK having a phase inverted from thatof the signal LSR on the basis of the pseudo-random pulse, bothgenerated from the pulse generators 300 a and 300 b. In the presentembodiment, any one of the signal LSR and the signal LSR_PSK is selectedas a signal having a duty smaller than 50% on the basis of a triggersignal PSKTRIG based on the pseudo-random pulse.

The distance image sensor of the indirect ToF system according to theembodiment of the present disclosure generates a pseudo-random pulse inthis manner and changes the phase of a light source outputting signaland a pixel modulation signal on the basis of the pseudo-random pulse.In other words, the phase can be inverted. By changing the phase of thelight source outputting signal and the pixel modulation signal on thebasis of the pseudo-random pulse, the distance image sensor of theindirect ToF system according to the embodiment of the presentdisclosure can decide whether or not light received by the image sensoris received light emitted from a light source of the distance imagesensor itself even in the case where a different distance image sensorthat simultaneously measures the distance to a same target exists.

<Application Example to Endoscopic Surgery System>

The technology according to the present disclosure (present technology)can be applied to various products. For example, the technologyaccording to the present disclosure may be applied to an endoscopicsurgery system.

FIG. 64 is a view depicting an example of a schematic configuration ofan endoscopic surgery system to which the technology according to anembodiment of the present disclosure (present technology) can beapplied.

In FIG. 64, a state is illustrated in which a surgeon (medical doctor)11131 is using an endoscopic surgery system 11000 to perform surgery fora patient 11132 on a patient bed 11133. As depicted, the endoscopicsurgery system 11000 includes an endoscope 11100, other surgical tools11110 such as a pneumoperitoneum tube 11111 and an energy device 11112,a supporting arm apparatus 11120 which supports the endoscope 11100thereon, and a cart 11200 on which various apparatus for endoscopicsurgery are mounted.

The endoscope 11100 includes a lens barrel 11101 having a region of apredetermined length from a distal end thereof to be inserted into abody cavity of the patient 11132, and a camera head 11102 connected to aproximal end of the lens barrel 11101. In the example depicted, theendoscope 11100 is depicted which includes as a rigid endoscope havingthe lens barrel 11101 of the hard type. However, the endoscope 11100 mayotherwise be included as a flexible endoscope having the lens barrel11101 of the flexible type.

The lens barrel 11101 has, at a distal end thereof, an opening in whichan objective lens is fitted. A light source apparatus 11203 is connectedto the endoscope 11100 such that light generated by the light sourceapparatus 11203 is introduced to a distal end of the lens barrel 11101by a light guide extending in the inside of the lens barrel 11101 and isirradiated toward an observation target in a body cavity of the patient11132 through the objective lens. It is to be noted that the endoscope11100 may be a forward-viewing endoscope or may be an oblique-viewingendoscope or a side-viewing endoscope.

An optical system and an image pickup element are provided in the insideof the camera head 11102 such that reflected light (observation light)from the observation target is condensed on the image pickup element bythe optical system. The observation light is photo-electricallyconverted by the image pickup element to generate an electric signalcorresponding to the observation light, namely, an image signalcorresponding to an observation image. The image signal is transmittedas RAW data to a CCU 11201.

The CCU 11201 includes a central processing unit (CPU), a graphicsprocessing unit (GPU) or the like and integrally controls operation ofthe endoscope 11100 and a display apparatus 11202. Further, the CCU11201 receives an image signal from the camera head 11102 and performs,for the image signal, various image processes for displaying an imagebased on the image signal such as, for example, a development process(demosaic process).

The display apparatus 11202 displays thereon an image based on an imagesignal, for which the image processes have been performed by the CCU11201, under the control of the CCU 11201.

The light source apparatus 11203 includes a light source such as, forexample, a LED (Light Emitting Diode) and supplies irradiation lightupon imaging of a surgical region to the endoscope 11100.

An inputting apparatus 11204 is an input interface for the endoscopicsurgery system 11000. A user can perform inputting of various kinds ofinformation or instruction inputting to the endoscopic surgery system11000 through the inputting apparatus 11204. For example, the user wouldinput an instruction or a like to change an image pickup condition (typeof irradiation light, magnification, focal distance or the like) by theendoscope 11100.

A treatment tool controlling apparatus 11205 controls driving of theenergy device 11112 for cautery or incision of a tissue, sealing of ablood vessel or the like. A pneumoperitoneum apparatus 11206 feeds gasinto a body cavity of the patient 11132 through the pneumoperitoneumtube 11111 to inflate the body cavity in order to secure the field ofview of the endoscope 11100 and secure the working space for thesurgeon. A recorder 11207 is an apparatus capable of recording variouskinds of information relating to surgery. A printer 11208 is anapparatus capable of printing various kinds of information relating tosurgery in various forms such as a text, an image or a graph.

It is to be noted that the light source apparatus 11203 which suppliesirradiation light when a surgical region is to be imaged to theendoscope 11100 may include a white light source which includes, forexample, an LED, a laser light source or a combination of them. Where awhite light source includes a combination of red, green, and blue (RGB)laser light sources, since the output intensity and the output timingcan be controlled with a high degree of accuracy for each color (eachwavelength), adjustment of the white balance of a picked up image can beperformed by the light source apparatus 11203. Further, in this case, iflaser beams from the respective RGB laser light sources are irradiatedtime-divisionally on an observation target and driving of the imagepickup elements of the camera head 11102 are controlled in synchronismwith the irradiation timings. Then images individually corresponding tothe R, G and B colors can be also picked up time-divisionally. Accordingto this method, a color image can be obtained even if color filters arenot provided for the image pickup element.

Further, the light source apparatus 11203 may be controlled such thatthe intensity of light to be outputted is changed for each predeterminedtime. By controlling driving of the image pickup element of the camerahead 11102 in synchronism with the timing of the change of the intensityof light to acquire images time-divisionally and synthesizing theimages, an image of a high dynamic range free from underexposed blockedup shadows and overexposed highlights can be created.

Further, the light source apparatus 11203 may be configured to supplylight of a predetermined wavelength band ready for special lightobservation. In special light observation, for example, by utilizing thewavelength dependency of absorption of light in a body tissue toirradiate light of a narrow band in comparison with irradiation lightupon ordinary observation (namely, white light), narrow band observation(narrow band imaging) of imaging a predetermined tissue such as a bloodvessel of a superficial portion of the mucous membrane or the like in ahigh contrast is performed. Alternatively, in special light observation,fluorescent observation for obtaining an image from fluorescent lightgenerated by irradiation of excitation light may be performed. Influorescent observation, it is possible to perform observation offluorescent light from a body tissue by irradiating excitation light onthe body tissue (autofluorescence observation) or to obtain afluorescent light image by locally injecting a reagent such asindocyanine green (ICG) into a body tissue and irradiating excitationlight corresponding to a fluorescent light wavelength of the reagentupon the body tissue. The light source apparatus 11203 can be configuredto supply such narrow-band light and/or excitation light suitable forspecial light observation as described above.

FIG. 65 is a block diagram depicting an example of a functionalconfiguration of the camera head 11102 and the CCU 11201 depicted inFIG. 64.

The camera head 11102 includes a lens unit 11401, an image pickup unit11402, a driving unit 11403, a communication unit 11404 and a camerahead controlling unit 11405. The CCU 11201 includes a communication unit11411, an image processing unit 11412 and a control unit 11413. Thecamera head 11102 and the CCU 11201 are connected for communication toeach other by a transmission cable 11400.

The lens unit 11401 is an optical system, provided at a connectinglocation to the lens barrel 11101. Observation light taken in from adistal end of the lens barrel 11101 is guided to the camera head 11102and introduced into the lens unit 11401. The lens unit 11401 includes acombination of a plurality of lenses including a zoom lens and afocusing lens.

An image pickup unit 11402 includes the image pickup element. The numberof image pickup elements which is included by the image pickup unit11402 may be one (single-plate type) or a plural number (multi-platetype). Where the image pickup unit 11402 is configured as that of themulti-plate type, for example, image signals corresponding to respectiveR, G and B are generated by the image pickup elements, and the imagesignals may be synthesized to obtain a color image. The image pickupunit 11402 may also be configured so as to have a pair of image pickupelements for acquiring respective image signals for the right eye andthe left eye ready for three dimensional (3D) display. If 3D display isperformed, then the depth of a living body tissue in a surgical regioncan be comprehended more accurately by the surgeon 11131. It is to benoted that, where the image pickup unit 11402 is configured as that ofstereoscopic type, a plurality of systems of lens units 11401 areprovided corresponding to the individual image pickup elements.

Further, the image pickup unit 11402 may not necessarily be provided onthe camera head 11102. For example, the image pickup unit 11402 may beprovided immediately behind the objective lens in the inside of the lensbarrel 11101.

The driving unit 11403 includes an actuator and moves the zoom lens andthe focusing lens of the lens unit 11401 by a predetermined distancealong an optical axis under the control of the camera head controllingunit 11405. Consequently, the magnification and the focal point of apicked up image by the image pickup unit 11402 can be adjusted suitably.

The communication unit 11404 includes a communication apparatus fortransmitting and receiving various kinds of information to and from theCCU 11201. The communication unit 11404 transmits an image signalacquired from the image pickup unit 11402 as RAW data to the CCU 11201through the transmission cable 11400.

In addition, the communication unit 11404 receives a control signal forcontrolling driving of the camera head 11102 from the CCU 11201 andsupplies the control signal to the camera head controlling unit 11405.The control signal includes information relating to image pickupconditions such as, for example, information that a frame rate of apicked up image is designated, information that an exposure value uponimage picking up is designated and/or information that a magnificationand a focal point of a picked up image are designated.

It is to be noted that the image pickup conditions such as the framerate, exposure value, magnification or focal point may be designated bythe user or may be set automatically by the control unit 11413 of theCCU 11201 on the basis of an acquired image signal. In the latter case,an auto exposure (AE) function, an auto focus (AF) function and an autowhite balance (AWB) function are incorporated in the endoscope 11100.

The camera head controlling unit 11405 controls driving of the camerahead 11102 on the basis of a control signal from the CCU 11201 receivedthrough the communication unit 11404.

The communication unit 11411 includes a communication apparatus fortransmitting and receiving various kinds of information to and from thecamera head 11102. The communication unit 11411 receives an image signaltransmitted thereto from the camera head 11102 through the transmissioncable 11400.

Further, the communication unit 11411 transmits a control signal forcontrolling driving of the camera head 11102 to the camera head 11102.The image signal and the control signal can be transmitted by electricalcommunication, optical communication or the like.

The image processing unit 11412 performs various image processes for animage signal in the form of RAW data transmitted thereto from the camerahead 11102.

The control unit 11413 performs various kinds of control relating toimage picking up of a surgical region or the like by the endoscope 11100and display of a picked up image obtained by image picking up of thesurgical region or the like. For example, the control unit 11413 createsa control signal for controlling driving of the camera head 11102.

Further, the control unit 11413 controls, on the basis of an imagesignal for which image processes have been performed by the imageprocessing unit 11412, the display apparatus 11202 to display a pickedup image in which the surgical region or the like is imaged. Thereupon,the control unit 11413 may recognize various objects in the picked upimage using various image recognition technologies. For example, thecontrol unit 11413 can recognize a surgical tool such as forceps, aparticular living body region, bleeding, mist when the energy device11112 is used and so forth by detecting the shape, color and so forth ofedges of objects included in a picked up image. The control unit 11413may cause, when it controls the display apparatus 11202 to display apicked up image, various kinds of surgery supporting information to bedisplayed in an overlapping manner with an image of the surgical regionusing a result of the recognition. Where surgery supporting informationis displayed in an overlapping manner and presented to the surgeon11131, the burden on the surgeon 11131 can be reduced and the surgeon11131 can proceed with the surgery with certainty.

The transmission cable 11400 which connects the camera head 11102 andthe CCU 11201 to each other is an electric signal cable ready forcommunication of an electric signal, an optical fiber ready for opticalcommunication or a composite cable ready for both of electrical andoptical communications.

Here, while, in the example depicted, communication is performed bywired communication using the transmission cable 11400, thecommunication between the camera head 11102 and the CCU 11201 may beperformed by wireless communication.

An example of an endoscopic surgery system to which the technologyaccording to the present disclosure can be applied has been described.The technology according to the present disclosure can be applied, fromwithin the configuration described above, for example, to the endoscope11100, (the image pickup unit 11402 of) the camera head 11102, (theimage processing unit 11412 of) the CCU 11201 and so forth.

It is to be noted here that, while an endoscopic surgery system has beendescribed as an example, the technology according to the presentdisclosure may be applied, for example, to a microscopic surgery systemor the like.

<Application Example of Moving Body>

The technology according to the present disclosure (present technology)can be applied to various products. For example, the technologyaccording to the present disclosure may be implemented as an apparatusthat is incorporated in any type of moving body such as an automobile,an electric car, a hybrid electric car, a motorcycle, a bicycle, apersonal mobility, an airplane, a drone, a ship, a robot and so forth.

FIG. 66 is a block diagram depicting an example of schematicconfiguration of a vehicle control system as an example of a mobile bodycontrol system to which the technology according to an embodiment of thepresent disclosure can be applied.

The vehicle control system 12000 includes a plurality of electroniccontrol units connected to each other via a communication network 12001.In the example depicted in FIG. 66, the vehicle control system 12000includes a driving system control unit 12010, a body system control unit12020, an outside-vehicle information detecting unit 12030, anin-vehicle information detecting unit 12040, and an integrated controlunit 12050. In addition, a microcomputer 12051, a sound/image outputsection 12052, and a vehicle-mounted network interface (I/F) 12053 areillustrated as a functional configuration of the integrated control unit12050.

The driving system control unit 12010 controls the operation of devicesrelated to the driving system of the vehicle in accordance with variouskinds of programs. For example, the driving system control unit 12010functions as a control device for a driving force generating device forgenerating the driving force of the vehicle, such as an internalcombustion engine, a driving motor, or the like, a driving forcetransmitting mechanism for transmitting the driving force to wheels, asteering mechanism for adjusting the steering angle of the vehicle, abraking device for generating the braking force of the vehicle, and thelike.

The body system control unit 12020 controls the operation of variouskinds of devices provided to a vehicle body in accordance with variouskinds of programs. For example, the body system control unit 12020functions as a control device for a keyless entry system, a smart keysystem, a power window device, or various kinds of lamps such as aheadlamp, a backup lamp, a brake lamp, a turn signal, a fog lamp, or thelike. In this case, radio waves transmitted from a mobile device as analternative to a key or signals of various kinds of switches can beinput to the body system control unit 12020. The body system controlunit 12020 receives these input radio waves or signals, and controls adoor lock device, the power window device, the lamps, or the like of thevehicle.

The outside-vehicle information detecting unit 12030 detects informationabout the outside of the vehicle including the vehicle control system12000. For example, the outside-vehicle information detecting unit 12030is connected with an imaging section 12031. The outside-vehicleinformation detecting unit 12030 makes the imaging section 12031 imagean image of the outside of the vehicle, and receives the imaged image.On the basis of the received image, the outside-vehicle informationdetecting unit 12030 may perform processing of detecting an object suchas a human, a vehicle, an obstacle, a sign, a character on a roadsurface, or the like, or processing of detecting a distance thereto.

The imaging section 12031 is an optical sensor that receives light, andwhich outputs an electric signal corresponding to a received lightamount of the light. The imaging section 12031 can output the electricsignal as an image, or can output the electric signal as informationabout a measured distance. In addition, the light received by theimaging section 12031 may be visible light, or may be invisible lightsuch as infrared rays or the like.

The in-vehicle information detecting unit 12040 detects informationabout the inside of the vehicle. The in-vehicle information detectingunit 12040 is, for example, connected with a driver state detectingsection 12041 that detects the state of a driver. The driver statedetecting section 12041, for example, includes a camera that images thedriver. On the basis of detection information input from the driverstate detecting section 12041, the in-vehicle information detecting unit12040 may calculate a degree of fatigue of the driver or a degree ofconcentration of the driver, or may determine whether the driver isdozing.

The microcomputer 12051 can calculate a control target value for thedriving force generating device, the steering mechanism, or the brakingdevice on the basis of the information about the inside or outside ofthe vehicle which information is obtained by the outside-vehicleinformation detecting unit 12030 or the in-vehicle information detectingunit 12040, and output a control command to the driving system controlunit 12010. For example, the microcomputer 12051 can perform cooperativecontrol intended to implement functions of an advanced driver assistancesystem (ADAS) which functions include collision avoidance or shockmitigation for the vehicle, following driving based on a followingdistance, vehicle speed maintaining driving, a warning of collision ofthe vehicle, a warning of deviation of the vehicle from a lane, or thelike.

In addition, the microcomputer 12051 can perform cooperative controlintended for automatic driving, which makes the vehicle to travelautonomously without depending on the operation of the driver, or thelike, by controlling the driving force generating device, the steeringmechanism, the braking device, or the like on the basis of theinformation about the outside or inside of the vehicle which informationis obtained by the outside-vehicle information detecting unit 12030 orthe in-vehicle information detecting unit 12040.

In addition, the microcomputer 12051 can output a control command to thebody system control unit 12020 on the basis of the information about theoutside of the vehicle which information is obtained by theoutside-vehicle information detecting unit 12030. For example, themicrocomputer 12051 can perform cooperative control intended to preventa glare by controlling the headlamp so as to change from a high beam toa low beam, for example, in accordance with the position of a precedingvehicle or an oncoming vehicle detected by the outside-vehicleinformation detecting unit 12030.

The sound/image output section 12052 transmits an output signal of atleast one of a sound and an image to an output device capable ofvisually or auditorily notifying information to an occupant of thevehicle or the outside of the vehicle. In the example of FIG. 66, anaudio speaker 12061, a display section 12062, and an instrument panel12063 are illustrated as the output device. The display section 12062may, for example, include at least one of an on-board display and ahead-up display.

FIG. 67 is a diagram depicting an example of the installation positionof the imaging section 12031.

In FIG. 67, on the vehicle 12100, the imaging section 12031 includesimaging sections 12101, 12102, 12103, 12104, and 12105.

The imaging sections 12101, 12102, 12103, 12104, and 12105 are, forexample, disposed at positions on a front nose, sideview mirrors, a rearbumper, and a back door of the vehicle 12100 as well as a position on anupper portion of a windshield within the interior of the vehicle. Theimaging section 12101 provided to the front nose and the imaging section12105 provided to the upper portion of the windshield within theinterior of the vehicle obtain mainly an image of the front of thevehicle 12100. The imaging sections 12102 and 12103 provided to thesideview mirrors obtain mainly an image of the sides of the vehicle12100. The image of the front of the vehicle 12100. The imaging sections12101 and 12105 provided to the rear bumper or the back door obtainsmainly an image of the rear of the vehicle 12100. The image of the frontobtained by the imaging sections 12101 and 12105 is used mainly todetect a preceding vehicle, a pedestrian, an obstacle, a signal, atraffic sign, a lane, or the like.

Incidentally, FIG. 20 depicts an example of photographing ranges of theimaging sections 12101 to 12104. An imaging range 12111 represents theimaging range of the imaging section 12101 provided to the front nose.Imaging ranges 12112 and 12113 respectively represent the imaging rangesof the imaging sections 12102 and 12103 provided to the sideviewmirrors. An imaging range 12114 represents the imaging range of theimaging section 12104 provided to the rear bumper or the back door. Abird's-eye image of the vehicle 12100 as viewed from above is obtainedby superimposing image data imaged by the imaging sections 12101 to12104, for example.

At least one of the imaging sections 12101 to 12104 may have a functionof obtaining distance information. For example, at least one of theimaging sections 12101 to 12104 may be a stereo camera constituted of aplurality of imaging elements, or may be an imaging element havingpixels for phase difference detection.

For example, the microcomputer 12051 can determine a distance to eachthree-dimensional object within the imaging ranges 12111 to 12114 and atemporal change in the distance (relative speed with respect to thevehicle 12100) on the basis of the distance information obtained fromthe imaging sections 12101 to 12104, and thereby extract, as a precedingvehicle, a nearest three-dimensional object in particular that ispresent on a traveling path of the vehicle 12100 and which travels insubstantially the same direction as the vehicle 12100 at a predeterminedspeed (for example, equal to or more than 0 km/hour). Further, themicrocomputer 12051 can set a following distance to be maintained infront of a preceding vehicle in advance, and perform automatic brakecontrol (including following stop control), automatic accelerationcontrol (including following start control), or the like. It is thuspossible to perform cooperative control intended for automatic drivingthat makes the vehicle travel autonomously without depending on theoperation of the driver or the like.

For example, the microcomputer 12051 can classify three-dimensionalobject data on three-dimensional objects into three-dimensional objectdata of a two-wheeled vehicle, a standard-sized vehicle, a large-sizedvehicle, a pedestrian, a utility pole, and other three-dimensionalobjects on the basis of the distance information obtained from theimaging sections 12101 to 12104, extract the classifiedthree-dimensional object data, and use the extracted three-dimensionalobject data for automatic avoidance of an obstacle. For example, themicrocomputer 12051 identifies obstacles around the vehicle 12100 asobstacles that the driver of the vehicle 12100 can recognize visuallyand obstacles that are difficult for the driver of the vehicle 12100 torecognize visually. Then, the microcomputer 12051 determines a collisionrisk indicating a risk of collision with each obstacle. In a situationin which the collision risk is equal to or higher than a set value andthere is thus a possibility of collision, the microcomputer 12051outputs a warning to the driver via the audio speaker 12061 or thedisplay section 12062, and performs forced deceleration or avoidancesteering via the driving system control unit 12010. The microcomputer12051 can thereby assist in driving to avoid collision.

At least one of the imaging sections 12101 to 12104 may be an infraredcamera that detects infrared rays. The microcomputer 12051 can, forexample, recognize a pedestrian by determining whether or not there is apedestrian in imaged images of the imaging sections 12101 to 12104. Suchrecognition of a pedestrian is, for example, performed by a procedure ofextracting characteristic points in the imaged images of the imagingsections 12101 to 12104 as infrared cameras and a procedure ofdetermining whether or not it is the pedestrian by performing patternmatching processing on a series of characteristic points representingthe contour of the object. When the microcomputer 12051 determines thatthere is a pedestrian in the imaged images of the imaging sections 12101to 12104, and thus recognizes the pedestrian, the sound/image outputsection 12052 controls the display section 12062 so that a squarecontour line for emphasis is displayed so as to be superimposed on therecognized pedestrian. The sound/image output section 12052 may alsocontrol the display section 12062 so that an icon or the likerepresenting the pedestrian is displayed at a desired position.

An example of a vehicle control system to which the technology accordingto the present disclosure can be applied has been described. Thetechnology according to the present disclosure can be applied to theimaging section 12031 or the like in the configuration described above.

2. SUMMARY

As described above, according to the embodiment of the presentdisclosure, there is provided a configuration that is used in a camerasystem that adopts the indirect ToF system and can be ready for variousmodulation frequencies with a simple configuration.

Although the preferred embodiments of the present disclosure have beendescribed in detail with reference to the accompanying drawings, thetechnical scope of the present disclosure is not limited to suchembodiments as described above. It is apparent that those who havecommon knowledge in the technical field of the present disclosure canconceive various alternations or modifications without departing fromthe technical scope described in the claims, and it is recognized thatalso they naturally belong to the technical scope of the presentdisclosure.

Further, the advantageous effects described in the present specificationare explanatory and exemplary to the last and are not restrictive. Inother words, the technology according to the present disclosure canplay, together with or in places of the advantageous effects describedabove, other advantageous effects that are apparent to those skilled inthe art from the description of the present specification.

It is to be noted that also such configurations as described belowbelong to the technical scope of the present disclosure.

(1)

A signal generation apparatus, including:

a first pulse generator configured to generate a pulse to be supplied toa light source that irradiates light to a distance measurement target;

a second pulse generator configured to generate a pulse to be suppliedto pixels that receive light reflected by the distance measurementtarget; and

a switching section configured to switch a setting of a modulationfrequency of the first pulse generator and the second pulse generatorwithin a predetermined period.

(2)

The signal generation apparatus according to (1) above, in which thepredetermined period is a period from the start of accumulation into thepixels to completion of reading out.

(3)

The signal generation apparatus according to (1) or (2) above, furtherincluding:

at least one signal outputting circuit for supplying signals to thefirst pulse generator and the second pulse generator, in which

the number of signal outputting circuits is smaller than the number ofmodulation frequencies to be set during the predetermined period.

(4)

The signal generation apparatus according to any one of (1) to (3)above, in which

the first pulse generator and the second pulse generator include:

-   -   a first counter configured to determine a phase of the pulse        using an input signal; and    -   a second counter configured to determine a frequency of the        pulse using the input signal; and

the switching section switches the setting for the second counter withinthe predetermined period.

(5)

The signal generation apparatus according to any one of (1) to (4)above, in which

the signal generation apparatus is used in a distance measurement sensorof an indirect type.

REFERENCE SIGNS LIST

-   -   201: Distance image sensor    -   202: Optical system    -   203: Sensor chip    -   204: Image processing circuit    -   205: Monitor    -   206: Memory    -   211: Light source apparatus    -   300: Pulse generator    -   310: Counter    -   320: Flip-flop    -   330: And gate    -   340: Counter    -   350: PLL    -   352: Light source driver    -   354: Light source    -   355: Inverter    -   356: Pixel modulation driver    -   358: Pixel

The invention claimed is:
 1. A signal generation apparatus, comprising: a first pulse generator circuit configured to generate a pulse to be supplied to a light source that irradiates light to a distance measurement target; a second pulse generator circuit configured to generate a pulse to be supplied to pixels that receive light reflected by the distance measurement target; and a switching circuit configured to switch a setting of a modulation frequency of the first pulse generator circuit and the second pulse generator circuit within a predetermined period, wherein the first pulse generator circuit and the second pulse generator circuit include: a first counter configured to determine a phase of the pulse using an input signal; and a second counter configured to determine a frequency of the pulse using the input signal; and the switching circuit is configured to switch the setting for the second counter within the predetermined period.
 2. The signal generation apparatus according to claim 1, wherein the predetermined period is a period from the start of accumulation into the pixels to completion of reading out.
 3. The signal generation apparatus according to claim 1, further comprising: at least one signal outputting circuit configured to supply signals to the first pulse generator circuit and the second pulse generator circuit, wherein the number of signal outputting circuits is smaller than the number of modulation frequencies to be set during the predetermined period.
 4. The signal generation apparatus according to claim 1, wherein the signal generation apparatus is used in a distance measurement sensor of an indirect type. 